JP2016030030A - Biological information detection mat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological information detection mat capable of detecting a body motion vibration with high sensitivity.SOLUTION: A biological information detection mat 1 includes: a first substrate 2; a piezoelectric element 3 arranged integrally with the first substrate 2 and detecting vibration of the first substrate 2; and a spacer 4 arranged integrally with the first substrate 2 and forming two ares having different elastic coefficients from each other in contact with each other on a lower side of the first substrate 2. The spacer 4 constitutes one of the two areas having different elastic coefficients from each other. The piezoelectric element 3 is arranged across the two areas formed on the lower side of the first substrate 2 and having different elastic coefficients or arranged from the neighborhood of a boundary of the two areas in the other, which is different from the one of the two areas, to an opposite side of the boundary.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a planar biological information detection mat for detecting biological information.

  Heart rate, respiration, and body movements are detected to prevent sudden accidents while sleeping in the elderly and sick, and to create a comfortable healing environment and improve the efficiency of nursing in an aging society in the future. It is extremely useful.

  Conventionally, heartbeats are generally measured by placing a plurality of electrodes on the body, and breathing is generally measured by placing a tube in the nostril. However, in that case, since the monitor is expensive and takes an installation place, the measurement is limited to only a severely ill patient. For this reason, general patients and elderly people at home cannot inform nurses or nurses of sudden changes due to heart disease or cerebral infarction, and may die.

  On the other hand, in recent years, a biological information detection mat has been proposed that can be measured on body movement, heart rate, and respiration rate by simply putting it on a bed or a futon and sleeping by an elderly person wearing clothes. . In any measurement, a vibration is detected and a heartbeat / respiration signal is taken out through a predetermined frequency filter. Alternatively, when the amplitude exceeds a certain threshold intensity, it can be determined that the body movement.

  As the vibration detection means for the biological information detection mat, a pressure sensing method for detecting the internal pressure of the mat (Japanese Patent Laid-Open No. 2000-107154: Patent Document 1) and a method using a change in capacitance (Japanese Patent Laid-Open No. 10-14889) : Patent Document 2) and the like have been proposed. In particular, when a piezoelectric element is used as a detection means, it is possible to detect a signal with high sensitivity. In particular, when a piezoelectric cable is used, it is relatively inexpensive and can be arranged only at a necessary location, so that the efficiency is high. It is possible to detect vibrations well (Japanese Patent Laid-Open No. 2005-160650: Patent Document 3).

  In the apnea syndrome determination device disclosed in Patent Document 3, a plurality of piezo cables (piezoelectric cables) arranged at equal intervals in a cable base sheet (biological information detection mat) is placed under the subject's body. The pressure signal including the pressure fluctuation of the heartbeat motion of the subject is detected.

  As described above, when the biological information detection mat using the piezoelectric cable is used, depending on the use situation of the user, a sheet may be laid on a thick mattress, and the user may sleep on his / her back. In particular, such cases can be seen in general accommodation facilities, hospitals, and nursing care facilities. In such a case, the biological information detection mat is arranged under a thick mattress. In this case, weak vibrations such as heartbeats and breathing are attenuated in the thick (about 30 cm maximum) mattress before reaching the information detection mat, and thus a biological signal such as heartbeats and breathing is detected. There is a problem that it becomes difficult.

  The biological information detection mat using the piezoelectric cable is a type in which vibration is transmitted to a substrate to which the piezoelectric cable is fixed, and the vibration of the substrate is detected. Therefore, when the biological information detection mat is disposed on a hard surface (for example, a bottom plate of a bed, a flooring floor or a tatami mat), the amplitude of the substrate is reduced, and detection sensitivity, that is, S / N. There is a problem that the ratio deteriorates.

JP 2000-107154 A Japanese Patent Laid-Open No. 10-14889 JP 2005-160650 A

  Accordingly, an object of the present invention is to provide a biological information detection mat that can detect body motion vibration with high sensitivity even when placed under a thick mattress or on a hard surface.

In order to solve the above problems, the biological information detection mat of the present invention is
A first substrate;
A piezoelectric element that is provided integrally with the first substrate and detects vibration of the first substrate;
A spacer that is integrally provided on the first substrate, and that is provided on the lower side of the piezoelectric element or the first substrate to form two regions having mutually different elastic coefficients adjacent to each other;
The spacer constitutes one of the two regions having different elastic coefficients from each other,
The piezoelectric element is arranged over the two regions having different elastic coefficients from each other, or from the vicinity of the boundary between the two regions in the other of the two regions different from the one to the opposite side of the boundary. It is characterized by being.

但し
Ｗ：上記第１の基板における上記境界に平行な方向への幅(mm)
ｈ：上記第１の基板の厚さ(mm)
Ｌ：上記境界から上記境界に対向する端部までの距離(mm)
Ｅ_f：上記第１の基板の曲げ弾性率(ＭＰa) Moreover, in the biological information detection mat of one embodiment,
The vicinity of the boundary between the two regions is a region in which the distance x (mm) from the boundary between the two regions is represented by the following formula in the one of the two regions.

W: width in the direction parallel to the boundary in the first substrate (mm)
h: thickness of the first substrate (mm)
L: Distance from the boundary to the end facing the boundary (mm)
E _f : bending elastic modulus (MPa) of the first substrate

Moreover, in the biological information detection mat of one embodiment,
A second substrate disposed below the first substrate and the piezoelectric element;
Two regions having different elastic coefficients are formed between the first substrate and the second substrate.

Moreover, in the biological information detection mat of one embodiment,
The first substrate is divided into a plurality of partial substrates along a boundary between the two regions,
The dividing position of the first substrate is on the boundary between the two regions or on the other side of the two regions with respect to the boundary between the two regions.

Moreover, in the biological information detection mat of one embodiment,
The other of the two regions having different elastic coefficients is composed of an elastic body.

Moreover, the body motion sensor of other embodiment is
A piezoelectric element that detects the movement of the human body and outputs a body movement signal;
A temperature measuring unit that is thermally connected to the piezoelectric element, measures the temperature of the piezoelectric element, and outputs a temperature signal;
A body motion determination unit that determines whether or not the intensity of the body motion signal from the piezoelectric element exceeds a preset threshold value and determines the presence or absence of body motion;
Based on the temperature signal from the temperature measuring unit, a time differential value of the measured temperature is calculated, and a value obtained by multiplying the calculated time differential value of the measured temperature by a constant is the body motion signal from the piezoelectric element or the above And a temperature correction unit that corrects the influence of the temperature on the body movement signal by adding or subtracting to the threshold value in the body movement determination unit.

In the body motion sensor of one embodiment,
The piezoelectric element is a piezoelectric film or a piezoelectric cable.

In the body motion sensor of one embodiment,
The temperature measuring unit is any one of a thermocouple, a thermistor, and a thermopile.

In the body motion sensor of one embodiment,
A heating unit for heating the piezoelectric element and the temperature measuring unit;
The temperature correction unit includes a time differential value of the measured temperature and a voltage value of the body motion signal based on a temperature signal from the temperature measurement unit heated by the heating unit and a body motion signal from the piezoelectric element. The above constant is obtained by performing a linear approximation to obtain the slope of the approximate straight line.

Moreover, the sleep sensing system of other embodiment is
With the body motion sensor
further,
A sleep stage calculation unit that calculates a sleep stage based on the number of body movements determined by the body movement determination unit in the body movement sensor;
Based on the body motion signal from the body motion sensor,
Based on the body motion signal from the body motion sensor, a respiration detection unit that detects respiration,
At least one of a snoring detection unit for detecting snoring based on the body motion signal from the body motion sensor is provided.

  As is clear from the above, in the biological information detection mat of the present invention, one of the two regions having different elastic coefficients is constituted by the spacer. And the said piezoelectric element is arrange | positioned ranging from the vicinity of the boundary of the said 2 area | region in the other of the said 2 area | region to the other side of the said boundary over the said 2 area | region.

  Therefore, when the body motion is transmitted to the living body information detection mat, the first substrate located on the other upper side of the two regions having different elastic coefficients is displaced in the thickness direction and vibrates. In that case, a tensile force acts mainly on the piezoelectric element located on the other of the two regions, and a voltage signal is generated between both electrodes of the piezoelectric element. Further, the amplitude of the piezoelectric element increases due to the presence of the other of the two regions having the larger elastic coefficient, so that the S / N ratio of the voltage signal is improved.

  On the other hand, the piezoelectric element located on the one of the two regions formed by the spacer is relatively difficult to vibrate. Therefore, the piezoelectric element is bent at the boundary between the one of the two regions and the other, and a bending force acts, and a larger signal strength is generated between both electrodes of the piezoelectric element. Therefore, it is possible to further improve the S / N ratio.

  That is, according to the present invention, it is possible to improve sensitivity when detecting body motion vibration.

It is a schematic diagram in the biological information detection mat of this invention. It is a schematic diagram of the biometric information detection mat different from FIG. FIG. 3 is a side view of FIG. 2. It is explanatory drawing of the experimental method for determining (alpha), (beta), (gamma) in Formula (3). It is a schematic diagram of the biometric information detection mat different from FIG. 1 and FIG. FIG. 6 is a schematic diagram of a biological information detection mat different from those in FIGS. 1, 2, and 5. FIG. 7 is a schematic view of a biological information detection mat different from those in FIGS. 1, 2, 5, and 6. FIG. 8 is a schematic diagram of a biological information detection mat different from those in FIGS. 1, 2, and 5 to 7. It is a schematic diagram of the biological information detection mat different from FIG.1, FIG.2, FIG.5-8. FIG. 10 is a schematic view of a biological information detection mat different from those in FIGS. 1, 2, and 5 to 9. It is a block diagram of the sleep sensing system using the biometric information detection mat shown in FIG. It is explanatory drawing of the correction value calculation method in the block diagram shown in FIG. It is explanatory drawing of the effect of the temperature correction of the biometric information detection mat shown in FIG. It is a block diagram of the sleep sensing system different from FIG. It is operation | movement explanatory drawing of the body motion frequency calculation part in FIG. It is a schematic diagram in the biological information detection mat different from FIG.1, FIG.2, FIG.5-10. FIG. 17 is a schematic diagram of a biological information detection mat different from those in FIGS. 1, 2, 5 to 10, and 16. FIG. 18 is a schematic diagram of a biological information detection mat different from those shown in FIGS. It is explanatory drawing of the influence of the temperature change with respect to the generation signal of a piezoelectric element. FIG. 19 is a schematic plan view of a biological information detection mat different from FIGS. 1, 2, 5 to 10, and 16 to 18. It is a figure which shows the state before affixing a piezoelectric cable in FIG. It is a figure which shows the difference in the generation | occurrence | production signal regarding the sticking direction of the piezoelectric cable with a curvature, and the direction of deformation | transformation. It is an external view of the apparatus which deform | transforms a biometric information detection mat. It is explanatory drawing of the experimental data shown in FIG. It is a figure which shows the effect which removes the curvature of a piezoelectric cable. It is explanatory drawing of the calculation method of the curvature in a piezoelectric cable. It is a figure which shows the correlation with the curvature and peak signal strength in a piezoelectric cable. It is the schematic of a piezoelectric cable curvature removal apparatus. It is a cross-sectional schematic diagram of the piezoelectric cable which removed the curvature.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

-1st Embodiment FIG. 1: is a schematic diagram in the biometric information detection mat of this Embodiment. 1A is a cross-sectional view, and FIG. 1B is a bottom view. FIG. 1 (a) is a cross-sectional view taken along the line AA 'in FIG. 1 (b).

  Here, in this specification, the “thickness direction” refers to a direction perpendicular to the installed surface when the biological information detection mat is installed in the bed.

  The biometric information detection mat 1 includes a substrate 2 as a first substrate, a piezoelectric cable 3 and a spacer 4. The piezoelectric cable 3 is connected to the substrate 2 with a double-sided tape over substantially the entire length and is integrally formed. Further, as shown in FIG. 1B, the spacer 4 is integrally formed by being connected to the substrate 2 with an adhesive over substantially the entire width excluding the region through which the piezoelectric cable 3 penetrates.

  As the piezoelectric cable 3, for example, “Vibetek10” manufactured by Ormal Electronics was used. The substrate 2 is made of ABS (acrylonitrile, butadiene, styrene) resin, has a size of 30 cm × 30 cm square, and has a thickness of 1 mm to 10 mm. As the spacer 4, for example, aluminum is used, the thickness is, for example, 10 mm, and the size (width) in the direction perpendicular to the thickness is, for example, 10 mm.

  Although not shown in order to avoid complications, positive and negative lead wires are drawn out from the piezoelectric cable 3 and connected to an amplifier. The voltage signal amplified by the amplifier is converted into a digital signal through an AD converter and a filtering circuit, and biological information such as a body motion signal, a respiratory signal, and a heartbeat signal is acquired and fed back to the user. It is possible to build a system.

  The biometric information detection mat 1 is inserted on the user's mattress side. In such a case, if the user touches the user directly, the user may feel a foreign object and sleep may be disturbed. It is desirable to be installed through a mattress having a thickness of 3 cm to 10 cm. However, depending on the user, there is no mattress, and there is a case where a sheet is laid on the mattress and the user sleeps on the mattress. Further, the surface on which the biological information detection mat 1 is laid is desirably a resilient surface such as the mattress, but may be disposed on a bed base plate, flooring, tatami or the like that does not have elasticity.

  When the biological information detection mat 1 is used for the purpose of detecting respiration and heartbeat, the diaphragm and the heart are the main vibration sources. Therefore, the biological information detection mat 1 is arranged so that the vicinity of the center of the biological information detection mat 1 is located immediately below the diaphragm and the heart.

  In the present embodiment, the region 5 where the void is present corresponds to the region where the spacer 4 is not present, and the region 6 where the void is not present corresponds to the region where the spacer 4 is present. Moreover, the piezoelectric cable 3 is arrange | positioned over both the area | region 5 where a space | gap exists, and the area | region 6 where a space | gap does not exist.

  That is, in the present embodiment, the “one of the two regions having different elastic coefficients” is configured as the “region 6 in which no gap exists”. On the other hand, “the other of the two regions” is constituted by the “region 5 in which a gap exists”.

  Hereinafter, effects of the present embodiment will be described. When the body movement is transmitted to the biological information detection mat 1, the substrate 2 in the region 5 where the air gap exists is displaced in the thickness direction and vibrates. At that time, a tensile force is mainly applied to the piezoelectric cable 3 in the region 5 where the air gap exists, and a voltage signal is generated between both electrodes of the piezoelectric cable 3 due to a piezoelectric effect due to a shear stress caused by the tensile force. Since the amplitude of the piezoelectric cable 3 when the same pressure is applied in the thickness direction is increased due to the presence of the region 5 where the gap exists, the sensitivity can be improved by contributing to the improvement of the S / N ratio. Further, since the piezoelectric cable 3 in the region 6 where no air gap exists is relatively difficult to vibrate, the piezoelectric cable 3 is bent at the boundary between the region 5 where the air gap exists and the region 6 where no air gap exists. Therefore, a larger signal strength can be obtained by the piezoelectric effect due to the vertical stress caused by the bending force, and it is possible to further improve the sensitivity by contributing to further improvement of the S / N ratio.

  In general, the piezoelectric effect due to the vertical stress on the piezoelectric cable 3 is larger than the piezoelectric effect due to the shear stress. However, the biometric information detection mat using the conventional piezoelectric cable uses the latter effect mainly due to the pulling force and is inefficient. On the other hand, in the present embodiment, the former is actively used, and a remarkable effect that the vibration in the thickness direction can be effectively detected is achieved.

  In the present embodiment, if the piezoelectric cable 3 is arranged over both the region 5 where the air gap exists and the region 6 where the air gap does not exist, the effect of the present invention is generated, and the size and material are described in the description. It is not limited. Moreover, although the piezoelectric cable 3 is arrange | positioned in the approximate center in the extension direction of the spacer 4 of the board | substrate 2 as shown in FIG. 1, it is not limited to this. For example, it may be arranged near the periphery of the substrate 2. In FIG. 1, one piezoelectric cable 3 is arranged in the region 6 where no gap exists, but a plurality of piezoelectric cables 3 may be arranged.

  Furthermore, although the piezoelectric cable 3 is arranged in a straight line, the present invention is not limited to this and may be arranged in a curved line.

  The piezoelectric cable 3 is disposed on the opposite side of the two principal surfaces of the substrate 2 to the side where the living body exists, but is formed integrally with the substrate 2 so as to detect vibration of the substrate 2. It should be. That is, the piezoelectric cable 3 may be arranged on the side where the living body exists, or may be arranged embedded in the substrate 2.

Second Embodiment FIG. 2 is a schematic diagram of a biological information detection mat according to the present embodiment. However, FIG. 2A is a cross-sectional view and FIG. 2B is a bottom view. FIG. 2A is a cross-sectional view taken along the line BB ′ in FIG. FIG. 3 is a side view of FIG.

  The biometric information detection mat 11 includes a substrate 12 as a first substrate, a piezoelectric cable 13 and a spacer 14. The piezoelectric cable 13 is connected to the substrate 12 with a double-sided tape over substantially the entire length and is integrally formed. The spacer 14 is integrally formed by being connected to the substrate 12 with an adhesive. The size, material, and usage method are the same as those in the first embodiment, and a description thereof will be omitted.

In the present embodiment, the region 15 where the void 14 exists corresponds to the region where the spacer 14 does not exist, while the region 16 where the void 14 does not exist corresponds to the region where the spacer 14 exists. This is the same as in the first embodiment. The piezoelectric cable 13 is disposed in a region 15 where a gap exists. In this case, the piezoelectric cable 13 is also disposed in “the vicinity of the region 16 where no air gap exists”, which is a region where the distance from the spacer 14 in the region 15 where the air gap exists is within x ₀ .

  Next, the operation in this embodiment will be described. In the vicinity of the region 16 where no gap is present, the substrate 12 is relatively less likely to vibrate. Therefore, the piezoelectric cable 13 is largely bent in the vicinity of the region 16 where no gap is present, and the bending is performed in the same manner as in the first embodiment. A large signal intensity can be obtained by the piezoelectric effect due to the vertical stress caused by the force, which contributes to further improvement of the S / N ratio and further increases the sensitivity.

  In the present embodiment, it is not necessary to provide a hole or groove for inserting the piezoelectric cable 13 in one spacer 14 as compared with the case of the first embodiment. Therefore, the effects of simplification of the manufacturing process and cost reduction can be achieved.

Next, the “region where the piezoelectric cable 13 needs to be arranged” that can generate the effect of the present embodiment, that is, the range (distance x ₀ ) in the “near the region 16 where no gap exists” will be described. .

但し
Ｅ_f：曲げ弾性率(ＭＰa)
Ｆ：力(Ｎ)
Ｌ：支点間距離(mm)
Ｗ：試験片の幅(mm)
ｈ：試験片の厚さ(mm)
ｓ：撓み(mm) According to JIS k7074, the definition formula of the flexural modulus in the three-point bending test is as follows.

Where E _f : flexural modulus (MPa)
F: Force (N)
L: Distance between fulcrums (mm)
W: Specimen width (mm)
h: Test piece thickness (mm)
s: Deflection (mm)

このように、撓み量ｓは、材料の曲げ弾性率Ｅ_fと、形状パラメータＬ,Ｗ,ｈと、力Ｆとで記述することができる。ここで、上記「空隙が存在しない領域１６近傍」の領域を表すスペーサー１４からの距離ｘ₀は、基板１２が撓んだ場合に基板１２の曲率が最も大きくなる位置である。そこで、距離ｘ₀を求めるために、式(２)と同様の次式(３)を立て、実験結果に合うように式(３)中のＡ,α,β,γを決定する。また、曲げ弾性率Ｅ_fの依存性は小さいと予想されるために、後で考慮することにする。ｘ₀は、基板１２の曲率が最大となる位置とスペーサー１４との基板１２の設置面に平行な方向への距離である。
ｘ₀＝Ａ・Ｗ^α・ｈ^β・Ｌ^γ …（３） When the above equation (1) is solved for the deflection s, the following equation (2) is obtained.

Thus, the deflection amount s can be described by the bending elastic modulus E _f of the material, the shape parameters L, W, h, and the force F. Here, the distance x ₀ from the spacer 14 representing the region “near the region 16 where no gap exists” is a position where the curvature of the substrate 12 becomes the largest when the substrate 12 is bent. Therefore, in order to obtain the distance x ₀ , the following equation (3) similar to equation (2) is established, and A, α, β, and γ in equation (3) are determined so as to match the experimental results. Also, since the dependence of the flexural modulus E _f is expected to be small, it will be considered later. x ₀ is the distance in the direction parallel to the installation surface of the substrate 12 between the position where the curvature of the substrate 12 is maximum and the spacer 14.
x ₀ = A · W ^α · h ^β · L ^γ (3)

  FIG. 4 is a diagram for explaining an experimental method for determining α, β, and γ. The biometric information detection mat having the same substrate 12 and spacer 14 as in the present embodiment is placed on a hard surface, and the shape of the substrate 12 when a constant load is applied from above is determined from the extending direction of the spacer 14. Observed. On the opposite side of the substrate 12 from the observation side, a graph paper was placed so as to be perpendicular to both the hard surface and the observation direction, and the shape (displacement) of the substrate 12 was read. In that case, as a device for applying the constant load, CreepMeter RE2-30005B manufactured by Yamaden Co., Ltd. was used. The applied load was 20N.

The experimental results are shown in Table 1.
Table 1

  In Table 1, “1” indicates the structure of the reference biological information detection mat. “2” and “3” are structures in which the distance L between the spacers is changed from “1”, and the size of the substrate 12 itself is changed without changing the shape of the spacer 14. “4” and “5” are structures in which the depth width W is changed from “1”, and the size of the substrate 12 itself and the depth of the spacer 14 are also changed. “6” and “7” are structures in which the thickness h of the substrate 12 is changed from “1”.

When “1”, “2”, and “3” are compared, the distance x ₀ tends to increase as the inter-spacer distance L increases, but the ratio of the distance x _{0 to} the inter-spacer distance L decreases. . This is presumably because the greater the distance L between the spacers, the easier the substrate 12 bends and the flat area near the spacer 14 becomes narrower. Further, when “1”, “4”, and “5” are compared, the distance x ₀ tends to increase as the depth width W increases. This is considered to be because as the depth width W increases, the substrate 12 becomes more difficult to bend and the flat region near the spacer 14 becomes wider. Further, when “1”, “6”, and “7” are compared, the distance x ₀ tends to increase as the thickness h increases. This is considered to be because the substrate 12 becomes more difficult to bend as the thickness h increases, and the flat region near the spacer 14 becomes wider.

による計算値を、表１における「計算値」の欄に記載している。尚、表１における「実験値」をｘ軸に「計算値」をｙ軸にとり、「１」〜「７」のデータに基づいて散布図を描くと、略傾き１の直線でよく近似でき、相関係数Ｒの二乗値(決定係数)は０.９７６であった。 In order to satisfy the experimental results shown in Table 1, A = 10 ⁻⁴ , α = 1, β = 1.3, and γ = 0.8, the following equation (4)

The calculated value is described in the “calculated value” column in Table 1. In addition, when the “experimental value” in Table 1 is taken on the x-axis and the “calculated value” is taken on the y-axis, and a scatter diagram is drawn based on the data of “1” to “7”, it can be approximated by a straight line having a substantially slope of The square value (determination coefficient) of the correlation coefficient R was 0.976.

但し
Ｌ：スペーサー１４間距離(mm)
Ｗ：基板１２の奥行き幅(mm)
ｈ：基板１２の厚さ(mm)
Ｅ_f：基板１２の曲げ弾性率(ＭＰa) Further, “8”, “9”, and “10” are the same in the shape of the substrate 12 in “1”, but with different constituent materials. That is, while the substrate 12 in “1” is the above ABS, “8” is Teflon (registered trademark), “9” is polyethylene, and “10” is PBI (polybenzimidazole). Yes. As the flexural modulus of the constituent material of the substrate 12 increases, the distance x ₀ tends to increase. This is considered to be because as the flexural modulus increases, the substrate 12 becomes more difficult to bend and the flat region near the spacer 14 becomes wider. In consideration of the flexural modulus of the material, the equation (4) is corrected to the following equation (5).

L: Distance between spacers (mm)
W: Depth width of substrate 12 (mm)
h: thickness of substrate 12 (mm)
E _f : flexural modulus of elasticity of substrate 12 (MPa)

  When the “experimental value” in Table 1 is taken on the x axis, the “calculated value” according to the above equation (5) is taken on the y axis, and a scatter diagram is drawn based on the data “1” to “10”, the approximate slope 1 The square value of the correlation coefficient R was 0.971. Further, it was confirmed that even if the shape of the substrate 12 was changed using different materials of the substrate 12, it could be well approximated by the above equation (5).

In living body information detection mat 11 in the present embodiment, using distance x ₀ above, distance x in the horizontal direction from spacer 14 covers both the region satisfying x ≦ x ₀ and other regions. Thus, the piezoelectric cable 13 is disposed. With this biometric information sensing mat 11, if the user's body movement is transmitted to the substrate 12, the distance from the spacer 14 is x = x ₀ near large Slight piezoelectric cable 13 occurs in, due to the bending forces perpendicular A large signal intensity can be obtained by the piezoelectric effect due to the stress, and an effect of improving the sensitivity by improving the S / N ratio can be achieved.

In the present embodiment, in the region 15 where the air gap exists, the piezoelectric cable 13 is arranged over both the region where the distance x in the horizontal direction from the spacer 14 satisfies x ≦ x ₀ and the other region. Thus, the effect of the present invention is generated, and the size and material are not limited to those described. Further, as shown in FIG. 2, the piezoelectric cable 13 is disposed in the vicinity of the approximate periphery of the substrate 12, but is not limited thereto. For example, it may be arranged near the center of the substrate 12. In FIG. 2, two piezoelectric cables 13 are arranged in a region satisfying x> x ₀ of a region 15 where a gap exists, but one or more than three may be arranged. Moreover, although the piezoelectric cable 13 is arrange | positioned at linear form, it is not limited to this, You may arrange | position at curvilinear form.

  The piezoelectric cable 13 is arranged on the opposite side of the two main surfaces of the substrate 12 to the side where the living body exists, but is formed integrally with the substrate 12 so as to detect vibration of the substrate 12. Just do it. That is, the piezoelectric cable 13 may be arranged on the side where the living body exists, or may be arranged embedded in the substrate 12.

Third Embodiment FIG. 5 is a schematic diagram of a biological information detection mat according to the present embodiment. However, FIG. 5A is a cross-sectional view, and FIG. 5B is a plan view. 5A is a cross-sectional view taken along the line CC ′ of FIG. 5B.

  The present embodiment is different from the first embodiment in that a second substrate is provided so as to adhere to a spacer.

  The biometric information detection mat 21 includes a first substrate 22, a piezoelectric cable 23, a spacer 24, and a second substrate 25. The piezoelectric cable 23 is connected to the first substrate 22 with a double-sided tape over substantially the entire length and is integrally formed. Further, as shown in FIG. 5B, the spacer 24 is integrally formed by being connected to the first substrate 22 with an adhesive over substantially the entire width excluding the region through which the piezoelectric cable 23 penetrates. The second substrate 25 is integrally formed on the opposite side of the spacer 24 from the first substrate 22 by being connected with an adhesive over the entire width. The size, material, and usage method are the same as those in the first embodiment.

  Thus, in the biological information detection mat 21 in the present embodiment, even if the second substrate 25 is present, the region 26 in which a gap exists between the first substrate 22 and the second substrate 25 A region 27 where no void exists is provided. Therefore, if the piezoelectric cable 23 is arranged over both the area 26 where the air gap exists and the area 27 where the air gap does not exist, the effect of the present invention occurs, and the size and material are not limited to the description. Absent.

  Further, by adopting the configuration of the present embodiment, the spacer 24 is not exposed, and the effect of eliminating the risk of injury to the user by the protrusions such as the spacer 24 can be achieved.

As shown in FIG. 5 (b), the piezoelectric cable 23 is arranged at the approximate center in the extending direction of the spacer 24 of the first substrate 22. However, the present invention is not limited to this. For example, it may be arranged near the periphery of the first substrate 22. Further, in FIG. 5, the piezoelectric cable 23 is arranged over both the region 26 where the air gap exists and the region 27 where the air gap does not exist. However, the invention is not limited thereto, with the distance x _0, in the region 26 where voids are present, the region in which the distance x in the horizontal direction from the spacer 24 satisfies x ≦ x ₀ Even if it arrange | positions the piezoelectric cable 23 over both other area | regions, it does not interfere.

-4th Embodiment FIG. 6: is a schematic diagram in the biometric information detection mat of this Embodiment. 6A is a cross-sectional view, and FIG. 6B is a plan view. 5A is a cross-sectional view taken along the line DD ′ of FIG. 5B.

  The present embodiment is different from the third embodiment in that the first substrate is divided by providing a dividing groove.

  The biological information detection mat 31 includes a first substrate 32, a piezoelectric cable 33, a spacer 34, and a second substrate 35. The piezoelectric cable 33 is connected to the first substrate 32 with a double-sided tape over substantially the entire length and is integrally formed. Further, as shown in FIG. 6B, the spacer 34 is integrally formed by being connected to the first substrate 32 with an adhesive over substantially the entire width excluding the region through which the piezoelectric cable 33 penetrates. The second substrate 35 is integrally formed on the side opposite to the first substrate 32 in the spacer 34 by being connected with an adhesive over the entire width. The size, material, and usage method are the same as those in the first embodiment.

  In the first substrate 32, the dividing groove 36 is formed along the spacer 34 in the vicinity of the boundary between the first substrate 32 and the second substrate 35. Is formed. The partial substrates 32a, 32b, and 32c divided by the dividing groove 36 are movable relative to each other, and are connected to each other by a piezoelectric cable 33 and various adhesive tapes (not shown). Alternatively, the entire biological information detection mat 31 is wrapped with a protective material (not shown) such as felt so that the partial substrates 32a, 32b, and 32c are connected to each other.

  As described above, in the biological information detection mat 31 according to the present embodiment, the region 37 where the void exists and the region 38 where the void does not exist are provided between the first substrate 32 and the second substrate 35. . The first substrate 32 is divided into three partial substrates 32a, 32b, and 32c by dividing grooves 36 formed along the spacers 34 in the vicinity of the boundary between the region 37 where the void is present and the region 38 where the void is not present. It is divided into Therefore, when the user's body movement is transmitted to the first substrate 32, the piezoelectric cable 33 is bent at the position of the dividing groove 36 in the first substrate 32. In that case, the bending rigidity of the entire biological information detection mat 31 is reduced by the bending rigidity of the first substrate 32. For this reason, the piezoelectric cable 33 is greatly bent, and the piezoelectric effect due to the vertical stress caused by the bending force is further increased, so that a larger signal strength can be obtained. That is, the effect of further improving the sensitivity by further improving the S / N ratio can be achieved.

  Here, the width of the dividing groove 36 in the first substrate 32 is preferably about 0.1 mm to 2 mm.

  In the present embodiment, the dividing groove 36 in the first substrate 32 is formed linearly along the spacer 34. However, the present invention is not limited to this, and it is only necessary that the location traversing the piezoelectric cable 33 is located in the vicinity of the boundary with the region 38 where no air gap exists. It doesn't matter if you go through the place.

In FIG. 6, the piezoelectric cable 33 is disposed over both the region 37 where the gap exists and the region 38 where the gap does not exist. However, the invention is not limited thereto, with the distance x _0, in the region 37 where voids are present, the region in which the distance x in the horizontal direction from the spacer 34 satisfies x ≦ x ₀ The piezoelectric cable 33 may be arranged over both the other regions. In that case, it is desirable to position the dividing groove 36 of the first substrate 32 at a distance x ₀ from the spacer 34 in the horizontal direction.

-5th Embodiment FIG. 7: is a schematic diagram in the biometric information detection mat of this Embodiment. 7A is a cross-sectional view, and FIG. 7B is a plan view. FIG. 7A is a cross-sectional view taken along the line EE ′ of FIG.

  The present embodiment is different from the third embodiment in that there are a plurality of regions where voids exist.

  The biometric information detection mat 41 includes a first substrate 42, a piezoelectric cable 43, a spacer 44, and a second substrate 45. The piezoelectric cable 43 is connected to the first substrate 42 with a double-sided tape over substantially the entire length and is integrally formed. Further, as shown in FIG. 7B, a plurality of spacers 44 (four in the present embodiment) are arranged at positions that divide the first substrate 42 into approximately three equal parts. Each spacer 44 is integrally connected to the first substrate 42 with an adhesive over substantially the entire width excluding the region through which the piezoelectric cable 43 penetrates. The second substrate 45 is integrally formed on the opposite side of the spacer 44 from the first substrate 42 by being connected with an adhesive over the entire width. The size, material, and usage method are the same as those in the first embodiment.

  As described above, in the biological information detection mat 41 according to the present embodiment, the four spacers 44 are arranged between the first substrate 42 and the second substrate 45 as shown in FIG. In this way, a plurality of (in this embodiment, three) voids 46 and a plurality of (in this embodiment, four) voids 47 are provided. Therefore, it is possible to provide a plurality of places where the piezoelectric cable 43 is bent, to obtain a signal of the piezoelectric effect due to the vertical stress in more detail, to further improve the S / N ratio, and to further improve the sensitivity. it can.

In FIG. 7, the piezoelectric cable 43 is arranged over both the region 46 where the gap exists and the region 47 where the gap does not exist. However, the present invention is not limited to this, and in the region 46 where the gap exists using the distance x ₀ , the distance x in the horizontal direction from the spacer 44 satisfies x ≦ x _0. The piezoelectric cable 43 may be disposed over both of the other regions.

For example, as shown in FIG. 7, two spacers 44 located on the outermost side among the four spacers 44 are defined as spacers 44a, and a region 46 having a void adjacent to the spacer 44a is a region 46a having a void. And And the both ends of the piezoelectric cable 43 are extended along the spacer 44a in the orthogonal direction. In that case, the distance x in the horizontal direction from the spacer 44a of portions extending along the spacer 44a in the piezoelectric cable 43 is to set so as to satisfy x ≦ x _0.

In that case, the portion of the piezoelectric cable 43 that extends along the spacer 44 a may be provided only on one end side of the piezoelectric cable 43. Further, each of the three piezoelectric cables bent in a U-shape is arranged in a region 46 where three gaps exist, and the distance x in the horizontal direction from the spacer 44 at both bent portions of each piezoelectric cable is set. , X ≦ x ₀ may be set.

-6th Embodiment FIG. 8: is a schematic diagram in the biometric information detection mat of this Embodiment. 8A is a cross-sectional view, and FIG. 8B is a plan view. 8A is a cross-sectional view taken along the line FF ′ of FIG. 8B.

  The present embodiment is different from the third embodiment in that an elastic body is present in the gap.

  The biological information detection mat 51 includes a first substrate 52, a piezoelectric cable 53, a spacer 54, a second substrate 55, and an elastic body 56. The piezoelectric cable 53 is connected to the first substrate 52 with a double-sided tape over substantially the entire length and is integrally formed. In addition, as shown in FIG. 8B, the spacer 54 is integrally formed by being connected to the first substrate 52 with an adhesive over substantially the entire width excluding the region through which the piezoelectric cable 53 penetrates. Further, the second substrate 55 is integrally formed on the side opposite to the first substrate 52 in the spacer 54 by being connected with an adhesive over the entire width. The elastic body 56 is inserted and fixed in a gap formed by the first substrate 52, the spacer 54, and the second substrate 55. The size, material, and usage method are the same as those in the first embodiment.

  In the third embodiment, the first substrate 22 is largely pushed down because the user's weight is large, or there is a protrusion on the user's body immediately above the biological information detection mat 21, and the second substrate. 25 may come into contact. In that case, there is a risk that the vibration due to the body movement in the first substrate 22 is hindered.

  Therefore, in the present embodiment, the elastic body 56 is inserted into the region 57 where there is a gap corresponding to the region where the spacer 54 does not exist. By doing so, it is possible to suppress the first substrate 52 from being pushed down by the elastic force of the elastic body 56 and to prevent the first substrate 52 from contacting the second substrate 55.

  As the elastic body 56, for example, a material having a relatively high resilience such as urethane, rubber, and foamed polyethylene is desirable. However, if the repulsive force is too strong, it becomes a factor that inhibits the vibration of the first substrate 52, and therefore there is an appropriate range for the repulsive force of the elastic body 56. It is sufficient that the elastic body 56 is recessed when the finger is lightly placed on the elastic body 56.

  The elastic body 56 is preferably as thick as 3 mm or more. On the other hand, if it is too thick, the user will feel a foreign object. Therefore, about 10-30 mm is desirable.

  In FIG. 8, the elastic body 56 is filled over the entire region 57 where the voids exist, but a part of the region 57 where the voids exist may be filled. Further, although the elastic body 56 exists over the entire thickness direction in the region 57 where the void exists, it is not always necessary. The elastic body 56 may be bonded integrally with either the first substrate 52 or the second substrate 55.

In FIG. 8, the piezoelectric cable 53 is disposed over both the region 57 where the gap exists and the region 58 where the gap does not exist. However, the present invention is not limited to this, and in the region 57 where the gap exists using the distance x ₀ , the distance x in the horizontal direction from the spacer 54 satisfies x ≦ x _0. The piezoelectric cable 53 may be arranged over both the other regions.

-7th Embodiment FIG. 9: is a schematic diagram in the biometric information detection mat of this Embodiment. 9A is a cross-sectional view, and FIG. 9B is a plan view. 9A is a cross-sectional view taken along the line GG ′ of FIG. 9B.

  The present embodiment is different from the third embodiment in that the spacer is arranged only at the center.

  The biological information detection mat 61 includes a first substrate 62, a piezoelectric cable 63, a spacer 64, and a second substrate 65. The piezoelectric cable 63 is connected to the first substrate 62 with a double-sided tape over substantially the entire length and is integrally formed. Further, as shown in FIG. 9B, the spacer 64 is connected to the first substrate 62 with an adhesive at the center in the extending direction of the spacer 64 over the entire width except for the region through which the piezoelectric cable 23 penetrates. It is configured integrally. The second substrate 65 is integrally formed on the opposite side of the spacer 64 from the first substrate 62 by being connected with an adhesive over the entire width. The size, material, and usage method are the same as those in the first embodiment.

  As described above, in the biological information detection mat 61 in the present embodiment, only one region 67 in which there is no gap corresponding to the region in which the spacer 64 exists is provided in the central portion in the extending direction of the spacer 64. The entire side is a region 66 where a gap exists. Therefore, two folds can be formed in the piezoelectric cable 63 in the region 67 where no gap exists, and an improvement in sensitivity due to an improvement in the S / N ratio can be expected.

In FIG. 9, the piezoelectric cable 63 is disposed over both the region 66 where the gap exists and the region 67 where the gap does not exist. However, the present invention is not limited to this, and in the region 66 where the gap exists using the distance x ₀ , the distance x in the horizontal direction from the spacer 64 satisfies x ≦ x _0. Even if it arrange | positions the piezoelectric cable 63 over both other area | regions, it does not interfere.

In this case, the value of the inter-spacer distance L used in the above equation (5) for calculating the distance x ₀ is twice the distance L ₂ from the side surface of the spacer 64 to the end of the first substrate 62. The reason for this is that the end of the first substrate 62 is an open end and the vibration amplitude is at the largest position, so that the same biological information detection mat 61 is connected side by side in two plane directions. This is because the first substrate 62 performs the same movement.

  In FIG. 9, the void in the region 66 where the void exists is depicted as a hollow state, but all or part of the void may be filled with an elastic body. By doing in this way, the risk that the 1st board | substrate 62 will inhibit the vibration of the 1st board | substrate 62 by contacting the 2nd board | substrate 65 in the left or right edge in FIG. 9 can be prevented.

  In each of the above embodiments, the piezoelectric cables 3, 13, 23, 33, 43, 53, and 63 are used as the piezoelectric elements. However, they may be replaced with piezoelectric films. However, the piezoelectric cable is preferable because the piezoelectric effect due to “elongation” and “break” is more remarkable than the piezoelectric film, and is relatively inexpensive.

  In the above embodiments, the piezoelectric cables 3, 13, 23, 33, 43, 53, 63 are connected to the substrates 2, 12 or the first substrates 22, 32, 42, 52, 62 with double-sided tape. And are integrally formed. However, it does not matter if it is integrally formed by bonding with an adhesive or the like.

  In each of the above embodiments, the voids in the regions 5, 15, 26, 37, 46, 56, 66, 66 where the voids exist are the piezoelectric cables 3, 13, 23, 33, 43, 53. , 63 across the entire width. That is, the substrate 2 depicted in FIGS. 1 (b), 2 (b), 5 (b), 6 (b), 7 (b), 8 (b), and 9 (b). , 12, 22, 32, 42, 52, 62 penetrate from the lower end to the upper end in the figure. However, the present invention is not limited to this, and a spacer is provided on the whole or a part of the upper end or / and the lower end of the substrate 2, 12, 22, 32, 42, 52, 62 in the above figure, The whole or part of the end of the gap may be closed.

In each of the above embodiments, the spacers 4, 14, 24, 34, 44, 54, and 64 are the same as those shown in FIGS. 1 (b), 2 (b), 5 (b), and 6 (b). 7B, FIG. 8B, and FIG. 9B, the substrates 2, 12, 22, 32, 42, 52, and 62 exist from the lower end to the upper end in the figure. However, the present invention is not limited to this, and spacers 4, 14, 24, 34, are provided on a part of the right side and the left side of the substrate 2, 12, 22, 32, 42, 52, 62 in the above figure. 44, 54 and 64 may be provided. In short, the piezoelectric element is arranged over both the region with and without the spacer, or the distance in the horizontal direction from the spacer within the x ₀ and the other regions. It suffices if it is arranged over both of the above.

  Further, in each of the above embodiments, the spacers 4, 14, 24, 34, 44, 54, 64 are the substrates 2, 12, the first substrates 22, 32, 42, 52, 62 and the second substrates 25, It is comprised separately from 35, 45, 55, 65. However, the present invention is not limited to this, and is integrated with the substrate 2, 12 and the first substrate 22, 32, 42, 52, 62 or the second substrate 25, 35, 45, 55, 65. You may comprise.

Eighth Embodiment Hereinafter, an embodiment relating to temperature correction of a detection value by the piezoelectric element made of the piezoelectric cable or the piezoelectric film will be described.

  FIG. 10 is a schematic diagram of the biological information detection mat according to the present embodiment. 10A is a plan view, and FIG. 10B is a cross-sectional view. However, FIG. 10B is a cross-sectional view taken along the line H-H ′ in FIG.

  In this biological information detection mat 71, a piezoelectric element 73 is integrally fixed to a substrate 72 as a base plate, and a signal generated by the piezoelectric element 73 is taken out to the outside through a piezoelectric element lead wire 74. Although not shown, the piezoelectric element lead wire 74 is composed of two wires, one of which is electrically connected to the anode side of the piezoelectric element 73 and the other is electrically connected to the cathode side. Further, a temperature measuring unit 75 that is thermally connected to the piezoelectric element 73 and integrally fixed to the substrate 72 is disposed, and a signal generated by the temperature measuring unit 75 is taken out to the outside by a temperature measuring unit lead wire 76. It is. Although not shown, the temperature measuring part lead wire 76 is composed of two wires, one of which is electrically connected to the anode side of the temperature measuring part 75 and the other is electrically connected to the cathode side.

  The temperature measuring unit 75 can measure a relatively narrow range with high accuracy and is preferably placed in a bed futon, so it is preferably small, and specifically includes a thermocouple, a thermistor, a thermopile, and the like. The

  The piezoelectric element 73 and the temperature measuring unit 75 are fixed to the substrate 72. Further, a buffer material 77 is attached to the fixed surface of the substrate 72 between the piezoelectric element 73 and the temperature measuring unit 75, and the substrate 72 and the buffer material 77 sandwich the piezoelectric element 73 and the temperature measuring unit 75.

  FIG. 11 is a block diagram of a sleep sensing system using the present biological information detection mat 71. In FIG. 11, a temperature measuring unit 75 for measuring the temperature of the piezoelectric element 73 is disposed so as to be thermally connected to the piezoelectric element 73. The body motion signal output from the piezoelectric element 73 is measured by the voltage measuring unit 78. Specifically, the voltage measuring unit 78 is composed of an A / D converter. The temperature signal output from the temperature measuring unit 75 is measured by the temperature measuring unit 79. The temperature measurement unit 79 is specifically composed of an A / D converter.

  Further, based on the temperature data obtained by the temperature measuring unit 79, the time differential calculating unit 80 calculates a time differential value of the measured temperature. A correction value is calculated by the correction value calculation unit 81 based on the time differential value of the measured temperature, and the calculated correction value is added to the signal voltage data from the voltage measurement unit 78 by the addition unit. In this way, the influence of temperature on the signal voltage value representing body movement is corrected. Based on the corrected signal voltage value, the body motion frequency calculating unit 83 calculates the body motion frequency, and based on the calculated body motion frequency, the sleep stage calculating unit 84 calculates the sleep stage. Then, the calculated sleep stage is transmitted to the user by the display unit 85.

  That is, in the present embodiment, the body motion sensor includes the biological information detection mat 71, the voltage measurement unit 78, the temperature measurement unit 79, the time differentiation calculation unit 80, the correction value calculation unit 81, the addition unit 82, and the body motion frequency. The calculation unit 83 is used. Of these, the time differential calculation unit 80, the correction value calculation unit 81, and the addition unit 82 constitute the temperature correction unit. The body motion frequency calculation unit 83 is an example of the body motion determination unit.

FIG. 12 is an explanatory diagram of a method for calculating a correction value in the block diagram shown in FIG. A curve 86 in FIG. 12A shows a time change of the temperature measured by the temperature measuring unit 75 when the piezoelectric element 73 in FIG. 11 is heated by being brought into contact with a heating means such as a hot plate at time t _0. It is a plot. Curve 87 is a plot of the first derivative with respect to temperature. Here, the heating means starts heating the biological information detection mat 71 in a state where the temperature is sufficiently stabilized. In FIG. 12A, the reason why the peak of the first derivative is delayed from the heating start time t ₀ is that it takes time to transmit the influence of the temperature by the heating means to the temperature measuring unit 75, and the delay time. Is a few seconds.

  FIG. 12 (b) is a plot of the time change of the signal voltage generated in the piezoelectric element 73 due to the temperature change shown in FIG. 12 (a). The signal voltage changes due to the temperature change because the material of the piezoelectric element 73 is deformed by thermal expansion or thermal contraction due to the temperature change.

  FIG. 12C is a plot in which the time differential value of temperature is plotted on the horizontal axis and the signal voltage value from the piezoelectric element 73 (piezoelectric element signal voltage value) is plotted on the vertical axis. In this case, since both show a clear correlation, linear approximation of both is performed by the least square method, and the slope of the approximate straight line is obtained. The “inclination” thus obtained or the correction value calculation formula “inclination × time differential value of temperature × (−1)” using the inclination is stored in the correction value calculation unit 81. Then, the correction value calculation unit 81 calculates the correction value using the “tilt” or the “correction value calculation formula”.

  By adding the correction value to the signal voltage from the piezoelectric element 73 by the adder 82, the influence of the temperature on the signal voltage of the piezoelectric element 73 can be canceled.

  Note that the linear approximation and the calculation of the “tilt” described in FIGS. 12 (a) to 12 (c) may be performed by the sleep sensing system, or the results of the other devices may be used. You may store in the correction value calculation part 81 of a sensing system.

  Here, the reason why the signal voltage of the piezoelectric element 73 exhibits the above-described behavior due to temperature change will be described. The piezoelectric element 73 is thermally expanded or contracted by increasing or decreasing the temperature, and a polarization voltage is generated. The voltage generated in the piezoelectric element 73 approaches “0” by energizing the load or the voltage measuring unit 78 connected in parallel to the anode and the cathode of the piezoelectric element 73. The generated voltage of the element 73 is not affected. However, when the temperature changes rapidly, the energization cannot follow the change and affects the generated voltage of the piezoelectric element 73. Since the degree of this effect is proportional to the time derivative of temperature, the proportional constant (the “slope”) is obtained in advance and stored in the correction value calculation unit 81, and the value obtained by multiplying the proportional constant by the time derivative of temperature. Is subtracted from the signal intensity of the piezoelectric element 73 or added to the threshold value, the effect of correcting the influence of temperature can be obtained.

  Note that the linear approximation shown in FIG. 12C is basically a linear approximation passing through the origin in many cases. However, depending on the situation, instead of linear approximation, polynomial approximation, exponential approximation, logarithmic approximation, or power approximation may be used. In that case, (the value of the approximate expression for a certain temperature differential amount) × (−1) is the correction value.

  In FIG. 12C, the piezoelectric element signal voltage value changes in the direction of increasing with respect to the temperature rise, but conversely, it may change in the decreasing direction. This is because the direction in which the piezoelectric element material deforms due to thermal expansion varies depending on the form of the piezoelectric element 73, and depends on the environment around the piezoelectric element 73, and therefore generally varies from element to element. .

  Therefore, before shipping the product (biological information detection mat 71) in the present embodiment, it is desirable to obtain and store an approximate expression for each position of each temperature measuring unit 75 by the above-described method. When the user uses it, the process of obtaining the approximate expression is not necessary, and the correction value is calculated from the differential value of the temperature using the approximate expression obtained in advance, and the correction is performed.

  FIG. 13 is a diagram for explaining the effect of temperature correction in the biometric information detection mat 71. 13 (a) and 13 (b) are signal voltages from the piezoelectric element 73 in a state where the user lies on the biological information detection mat 71 and turns over so as to ride on the piezoelectric element 73. FIG. This is a plot of a time change of a certain “piezoelectric element signal voltage”. 13A shows the piezoelectric element signal voltage before correction, and FIG. 13B shows the corrected piezoelectric element signal voltage.

  As shown in FIG. 13 (a), before the correction, the signal voltage changes due to the temperature rise due to body temperature several seconds after the signal voltage is generated by the body movement, and whether the body movement has occurred twice. Looks like. However, according to FIG. 13B, it can be seen that the signal voltage change due to the temperature rise is canceled by the correction, and only the signal voltage due to body movement is generated. Therefore, the body motion frequency calculation unit 83 correctly calculates the body motion frequency, which is the number of times that the piezoelectric element signal voltage has exceeded the upper threshold value, as one time. This is nothing but the effect of the present embodiment.

  When the user is using the biological information detection mat 71, if the user turns over and moves out of the biological information detection mat 71, the body movement cannot be detected. Therefore, it is desirable that the substrate 72 has a certain size. For example, it is desirable that the vertical direction (human height direction) is about 20 cm to 40 cm, and the horizontal direction (human horizontal direction) is about 20 cm to 80 cm.

  The substrate 72 is preferably flexible and thin. By doing so, the piezoelectric element 73 can efficiently detect the external force due to the body movement applied to the substrate 72. However, if the substrate 72 is too thin, the difference in the intensity of the generated signal with respect to the same external force between the position where the piezoelectric element 73 is located and the position where the piezoelectric element 73 is not present becomes large. Is desirable. Specifically, a material such as the ABS resin or multivesicular polyethylene is used, and the thickness is desirably about 1 mm to 5 mm.

  The buffer material 77 is preferably soft and thick. By doing so, the substrate 72 can be greatly deformed by an external force during body movement. Even when the biological information detection mat 71 is arranged on a hard bed, it is possible to detect body movement with high sensitivity. However, if the buffer material 77 is too thick, it will disturb the user's sleep, so it is necessary to make the thickness moderate. Specifically, a material such as urethane or rubber is used, and the thickness is preferably about 5 mm to 20 mm.

Ninth Embodiment In this embodiment, in a sleep sensing system using the same biological information detection mat 71 as in the eighth embodiment, a correction value due to temperature change is directly used as a threshold for body movement determination. It relates to what works.

  FIG. 14 shows a block diagram of the sleep sensing system in the present embodiment. In FIG. 14, the biological information detection mat 71, voltage measurement unit 78, temperature measurement unit 79, time differential calculation unit 80, correction value calculation unit 81, sleep stage calculation unit 84, and display unit 85 are the same as those in the eighth embodiment. The biological information detection mat 71, the voltage measurement unit 78, the temperature measurement unit 79, the time differentiation calculation unit 80, the correction value calculation unit 81, the sleep stage calculation unit 84, and the display unit 85 are exactly the same as in the eighth embodiment. The same reference numerals are used as in the case, and the description is omitted.

  In the present embodiment, the correction value calculated by the correction value calculation unit 81 is sent to the body movement frequency calculation unit 91. Then, the body motion frequency calculation unit 91 adds the correction value to the upper threshold and the lower threshold used for body motion determination. Then, as shown in FIG. 15, the body motion frequency calculation unit 91 calculates the body motion frequency based on the corrected upper threshold value and the corrected lower threshold value. By doing so, the change in the signal voltage that appears due to the temperature rise several seconds after the signal voltage is generated by the body movement falls below the corrected upper threshold, and the body movement frequency is correctly calculated as one time.

  That is, in the present embodiment, the body motion sensor is composed of the biological information detection mat 71, the voltage measurement unit 78, the temperature measurement unit 79, the time differentiation calculation unit 80, the correction value calculation unit 81, and the body motion frequency calculation unit 91. It is composed. Of these, the temperature differential calculation unit 80, the correction value calculation unit 81, and the body motion frequency calculation unit 91 constitute the temperature correction unit. The body motion frequency calculation unit 91 is an example of the body motion determination unit.

Tenth Embodiment The present embodiment relates to a body motion sensor using a piezoelectric film as the piezoelectric element.

  FIG. 16 is a schematic diagram of the biological information detection mat according to the present embodiment. 16A is a plan view, and FIG. 16B is a cross-sectional view. However, FIG. 16B is a cross-sectional view taken along the line I-I ′ in FIG.

  In the biometric information detection mat 101, a piezoelectric film 103 is integrally fixed to a substrate 102 as a base plate, and a signal generated from the piezoelectric film 103 is extracted to the outside through a piezoelectric film lead wire 104. Although not shown, the piezoelectric film lead wire 104 is composed of two wires, one of which is electrically connected to the anode side of the piezoelectric film 103 and the other is electrically connected to the cathode side. In addition, a plurality of temperature measuring sections 105 that are thermally connected to the piezoelectric film 103 and integrally fixed to the substrate 102 are arranged, and a signal generated by each temperature measuring section 105 is a plurality of temperature measuring section lead wires 106. Is taken out. Although not shown, each temperature measuring unit lead wire 106 is composed of two wires per one temperature measuring unit 105, one of which is electrically connected to the anode side of the temperature measuring unit 105 and the other is electrically connected to the cathode side. Has been.

  Specifically, the temperature measuring unit 105 includes a thermocouple, a thermistor, a thermopile, and the like. Here, the temperature measuring unit 105 includes a plurality of temperature measuring units 105a arranged above the horizontal center line in FIG. 16A in the piezoelectric film 103, and a plurality of temperature measuring units arranged on the center line. 105b and a plurality of temperature measuring sections 105c arranged below the center line.

  The piezoelectric film 103 and the temperature measuring unit 105 are fixed to the substrate 102. Further, a buffer material 107 is attached to a fixed surface of the substrate 102 between the piezoelectric film 103 and the temperature measuring unit 105, and the substrate 102 and the buffer material 107 sandwich the piezoelectric film 103 and the temperature measuring unit 105.

  The body motion sensor and the sleep sensing system using the biological information detection mat 101 of the present embodiment are the same as those in the block diagram of the body motion sensor and the sleep sensing system shown in FIG. 11 in the eighth embodiment. 79. Blocks of the body motion sensor and sleep sensing system shown in FIG. 11 except that a plurality of time differential calculation units 80, correction value calculation units 81, and addition units 82 are provided corresponding to each of the plurality of temperature measurement units 105. Since it is the same as that of the figure, the description is omitted. The plurality of addition units 82 are connected in series to the subsequent stage of the voltage measurement unit 78.

  The correction value calculation method in the sleep sensing system is basically the same as that in the eighth embodiment. That is, heating is performed by bringing heating means such as a hot plate into contact with each temperature measuring unit 105, and the eighth embodiment has been described with reference to FIGS. 12 (a), 12 (b), and 12 (c). The correction value is obtained through the same process as described above. Then, all the correction values obtained by the plurality of temperature measuring units 105 are summed and added to the signal voltage data from the piezoelectric film 103, whereby the influence of the temperature on the signal voltage value representing the body movement is corrected.

  The temperature measuring unit 105 is for detecting the temperature of the human body riding on the piezoelectric film 103. Therefore, when the arrangement intervals of the temperature measuring unit 105a, the temperature measuring unit 105b, and the temperature measuring unit 105c are too narrow, it is necessary to arrange a large number of the temperature measuring units 105, which is meaningless only at high cost. is there. On the other hand, if it is too wide, the influence of temperature may be overlooked, which is undesirable. Therefore, the interval between the temperature measuring sections 105 is desirably about 1 cm to 20 cm. In addition, the arrangement of the temperature measuring unit 105 is not limited to the arrangement shown in FIG. 16A, and may be arranged, for example, at intervals only in the left-right direction of the user who lies on his back.

Eleventh Embodiment This embodiment relates to a body motion sensor using a piezoelectric cable as the piezoelectric element.

  FIG. 17 is a schematic diagram of the biological information detection mat according to the present embodiment. FIG. 17A is a plan view and FIG. 17B is a cross-sectional view. However, FIG. 17B is a cross-sectional view taken along the line J-J ′ in FIG.

  In this biological information detection mat 111, a piezoelectric cable 113 is integrally fixed to a substrate 112 as a base plate, and a signal generated by the piezoelectric cable 113 is taken out by a piezoelectric cable lead wire 114. Although not shown, the piezoelectric cable lead wire 114 is composed of two wires, one of which is electrically connected to the anode side of the piezoelectric cable 113 and the other to the cathode side. Here, the piezoelectric cable 113 is disposed in a rectangular shape along the outer periphery of the substrate 112.

  In addition, a plurality of temperature measuring sections 115 that are thermally connected to the piezoelectric cable 113 and integrally fixed to the substrate 112 are arranged, and a signal generated by each temperature measuring section 115 is a plurality of temperature measuring section lead wires. At 116, it is taken out. Although not shown, each temperature measuring unit lead 116 is composed of two wires for each temperature measuring unit 115, one of which is electrically connected to the anode side of the temperature measuring unit 115 and the other is electrically connected to the cathode side. Has been.

  Specifically, the temperature measuring unit 115 includes a thermocouple, a thermistor, a thermopile, and the like. Here, the temperature measuring unit 115 includes a plurality of temperature measuring units 115a arranged above the center line in the horizontal direction in FIG. 17A in the piezoelectric cable 113, and a plurality of temperature measuring units arranged on the center line. 115b and a plurality of temperature measuring sections 115c arranged below the center line.

  The piezoelectric cable 113 and the temperature measuring unit 115 are fixed to the substrate 112. Further, a buffer material 117 is attached to a fixed surface of the substrate 112 on the piezoelectric cable 113 and the temperature measuring unit 115, and the piezoelectric cable 113 and the temperature measuring unit 115 are sandwiched between the substrate 112 and the buffer material 117.

  The body motion sensor and the sleep sensing system using the biological information detection mat 111 of the present embodiment are the same as those in the block diagram of the body motion sensor and the sleep sensing system shown in FIG. 11 in the eighth embodiment. 79. Blocks of the body motion sensor and sleep sensing system shown in FIG. 11 except that a plurality of time differential calculation units 80, correction value calculation units 81, and addition units 82 are provided corresponding to each of the plurality of temperature measurement units 115. Since it is the same as that of the figure, the description is omitted. The plurality of addition units 82 are connected in series to the subsequent stage of the voltage measurement unit 78.

  The correction value calculation method in the sleep sensing system is basically the same as that in the eighth embodiment. That is, heating is performed by bringing heating means such as a hot plate into contact with each individual temperature measuring unit 115, and in the eighth embodiment described with reference to FIGS. 12 (a), 12 (b), and 12 (c). The correction value is obtained through the same process as described above. Then, all the correction values obtained by the plurality of temperature measuring units 115 are summed and added to the signal voltage data from the piezoelectric cable 113, whereby the influence of the temperature on the signal voltage value representing the body movement is corrected.

Twelfth Embodiment The present embodiment relates to a body motion sensor having a heating unit for calculating a correlation equation between the time differential value of the temperature of the piezoelectric element and the signal voltage value of the piezoelectric element.

  FIG. 18 is a schematic diagram of the biological information detection mat according to the present embodiment. 18A is a plan view, and FIG. 18B is a cross-sectional view. However, FIG. 18B is a cross-sectional view taken along the line K-K ′ in FIG.

  In this biological information detection mat 121, a piezoelectric element 123 is integrally fixed to a substrate 122 as a base plate, and a signal generated from the piezoelectric element 123 is taken out by a piezoelectric element lead wire 124. Although not shown, the piezoelectric element lead 124 is composed of two wires, one of which is electrically connected to the anode side of the piezoelectric element 123 and the other is electrically connected to the cathode side. Further, a temperature measuring unit 125 that is thermally connected to the piezoelectric element 123 and integrally fixed to the substrate 122 is disposed, and a signal generated by the temperature measuring unit 125 is taken out to the outside by a temperature measuring unit lead 126. It is. Although not shown, the temperature measuring unit lead wire 126 is composed of two wires, one of which is electrically connected to the anode side of the temperature measuring unit 125 and the other is electrically connected to the cathode side.

  The temperature measuring unit 125 is preferably small because it can measure a relatively narrow range with high accuracy and is placed in the bed futon. Specifically, the temperature measuring unit 125 includes a thermocouple, a thermistor, a thermopile, and the like. The Further, a heating unit 127 that is thermally connected to the piezoelectric element 123 and the temperature measuring unit 125 and is integrally fixed to the substrate 122 is disposed so as to surround the piezoelectric element 123 and the temperature measuring unit 125. . Electric power to the heating unit 127 is supplied from the outside through the heating unit lead wire 128.

  The piezoelectric element 123, the temperature measuring unit 125, and the heating unit 127 are fixed to the substrate 122. Further, a buffer material 129 is attached to the fixed surfaces of the piezoelectric element 123, the temperature measuring unit 125, and the heating unit 127 on the substrate 122, and the piezoelectric element 123, the temperature measuring unit 125, and the heating unit 127 are connected by the substrate 122 and the buffer material 129. It is sandwiched.

  The biological information detection mat 121 in the present embodiment includes a heating unit 127 fixed to the substrate 122. Therefore, when performing linear approximation between the time differential value of the temperature and the signal voltage value, the heating means for heating the piezoelectric element 123 from the outside is not required, and the temperature measuring unit 125 in the user's usage environment The correlation equation between the time differential value of temperature and the signal voltage value from the piezoelectric element 123 can be calculated.

  As described above, according to the present embodiment, it is possible to prevent the influence of the manufacturing variation and the use environment for each body motion sensor, and to perform the correction for canceling the influence of the temperature with higher accuracy.

  Here, the configuration of the body motion sensor and the sleep sensing system using the biological information detection mat 121 in the present embodiment is the configuration of the body motion sensor and the sleep sensing system shown in FIG. 11 in the eighth embodiment. Or in the said 9th Embodiment, it is fundamentally the same as the structure of the body movement sensor and sleep sensing system which are shown in FIG.

  In the eighth embodiment to the twelfth embodiment, the substrate 72, 102, 112, 122 and the buffer material 77, 107, 117, 129 are provided. However, the substrate and the buffer material are necessarily required. Instead, based on the value obtained by multiplying the time derivative of the temperature measured by the temperature measuring units 75, 105, 115, and 125 by a constant, the signal voltage value or body motion frequency detection from the piezoelectric elements 73, 103, 113, and 123 is detected. It is sufficient to satisfy the requirement to correct the threshold value of the hour.

  In the eighth embodiment to the twelfth embodiment, the temperature measuring sections 75, 105, 115, and 125 are described as being thermally connected to the piezoelectric elements 73, 103, 113, and 123. ing. This indicates that the temperature of the piezoelectric elements 73, 103, 113, 123 in the vicinity of the temperature measuring units 75, 105, 115, 125 can be accurately measured. For example, if the temperature measuring sections 75, 105, 115, 125 are thermocouples or thermistors, the temperature measuring sections 75, 105, 115, 125 are directly connected to the piezoelectric elements 73, 103, 113, 123 or the thermal conductivity. It means that it is in contact through a high substance. Here, examples of the material having high thermal conductivity include heat-dissipating silicone. Furthermore, the degree of adhesion between the temperature measuring portions 75, 105, 115, and 125 and the piezoelectric elements 73, 103, 113, and 123 can be increased by a measure such as covering the whole with a metal foil such as aluminum.

  In the eighth embodiment to the twelfth embodiment, based on the corrected signal voltage values from the piezoelectric elements 73, 103, 113, and 123, the body motion frequency calculation units 83 and 91 and the sleep The stage calculation unit 84 is configured to calculate the sleep stage. However, the present invention is not limited to this, and the present invention can also be applied to the case where heartbeat, respiration, and snoring are extracted based on the corrected signal voltage value. Even in such a case, the effect of the correction of the signal voltage value occurs, and it is possible to extract signals resulting from them with high accuracy. For extraction of heartbeat signals and respiratory signals, refer to, for example, Japanese Patent Publication No. 11-505146.

  By the way, insomnia and fatigue are one of the unresolved problems in the developed society. A significant proportion of the population experiences sleep problems in some parts of their lives. Insufficiency of sleep leads to a decline in quality of life, reduced work ability, and, in more serious cases, mental disorders such as depression. For drivers and workers at risk of accidents, drowsiness can be a frequent cause of serious accidents. As a result, there is an increasing demand for devices aimed at improving the quality of sleep.

  Sleep is a dynamic behavior known to consist of four non-REM sleep NREMs that are stage I to stage IV and one stage REM sleep REM. Stages I and II are associated with light sleep, and stages III and IV are associated with deep sleep. Also, the non-REM sleep NREM is usually associated with minimal mental activity, and the REM sleep REM is associated with very active brain work and dreams. In a typical adult, sleep goes through Stage I, Stage II, Stage III, and Stage IV, going from Stage III to Stage I and back to REM Sleep REM. This cycle is repeated at intervals of approximately 90-100 minutes throughout the night. Deep sleep peaks at an early night and gradually becomes shallower at a late night.

  It is normal for the body to move during sleep, typically indicating light sleep (stage I and stage II). Also, when no body movement is seen, it typically indicates deep sleep (stage III and stage IV).

  “Sleep index” is a standard measurement value used to explain sleep, and includes the total sleep time TST, bedtime TIB, sleep latencies SOL, total sleep awakening after sleep, WASO and the number of waking after sleep NWAK, etc. One or more measurements. Primarily, exercise data is used to calculate a measurement value of one or more sleep indicators, but in particular other sensor data such as light and noise can be used to calculate a measurement value of a sleep indicator. Used with data.

  The “sleep quality index” is a measurement value used to explain the sleep quality of the user, and is a measurement value such as sleep efficiency SE, large exercise SM, or sleep segmentation SF. The sleep quality indicator is an indicator based on one of these measurements or based on a combination of two or more of these measurements.

The sleep efficiency SE is defined as a ratio of time spent sleeping in the bed, and can be calculated as follows.
SE = Total sleep time spent in bed / total time spent in bed = TST / TIB
Further, the total sleep time TST is calculated using the following equation.
TST = TIB-SOL-WASO
That is, the sleep efficiency SE is shown to the user as a percentage indicating that the higher the numerical value, the better the sleep.

  The large exercise SM is an indicator of sleep quality based on the number of large exercises that the user has performed while sleeping. This large exercise SM is obtained by analyzing overnight exercise data, setting a threshold, and counting the number of exercises above this threshold. The large exercise SM data is presented to the user as the total number of large exercises during the night or as the number of large exercises per hour during the night.

  The sleep segmentation SF is an index for monitoring how the user's nighttime sleep is segmented. The sleep subdivision SF includes an awakening time based on the number of waking hours after going to sleep NWAK. This sleep quality indicator is obtained by counting awakening longer than a specific time, eg, 5 minutes. This sleep subdivision SF is shown to the user as the total number of awakenings during the night or the average number of awakenings per hour.

Alternatively, a combined sleep quality indicator can be obtained by combining two or more of each sleep quality indicator described above. In general, this combined sleep quality indicator is calculated as a function of the above-described plurality of indicators and the like as described below.
Sleep quality index = f (SE, SM, SF,...)

For example, the combined sleep quality indicator is represented by a sleep efficiency SE expressed on a scale of 0 to 100, a large movement SM expressed on a scale of 0 to 100, and a scale of 0 to 100. Calculated as the sum of sleep subdivision SF.
Sleep quality index = s (SE) + s (SM) + s (SF)
However, s () represents a scaling function.

  This provides a sleep quality index from 0 to 300 that indicates the sleep quality of the user. This is associated with the “sleep quality indicator” above, and includes factors such as bedroom temperature, irregular “sleeping” and “wake-up” times, caffeine consumed, and / or alcohol content. .

  As described above, by obtaining the sleep stage from the body motion, the sleep quality index can be shown to the user, but it is necessary to obtain the sleep stage with high accuracy.

  As a sensor for detecting body movement, for example, there are piezoelectric sensors disclosed in Japanese Patent No. 4256660 and Japanese Patent No. 4029177. These piezoelectric sensors are arranged in a bed mattress and measure body movements.

  As a sleep stage detection method using the piezoelectric sensor, for example, there are the following methods. That is, the body motion frequency that is the frequency of body motion occurring within a certain time (for example, 30 seconds) and the sleep stage composed of “wakefulness”, “REM sleep”, “NONREM sleep I”, and “NONREM sleep II” The correlation is obtained in advance. Then, the body motion frequency of the subject is measured, and the sleep stage is calculated based on the above phase.

  Here, the correlation between the body motion frequency and the sleep stage is related to the detection of the body motion, and the electroencephalogram recording method EEG, electrocardiogram recording method EOG, electromyogram recording method EMG, electrocardiogram recording method ECG, etc. To measure the sleep stage. The body motion detection data thus obtained and the sleep stage are obtained. Further, body motion detection in that case is determined by whether or not the amplitude of the body motion signal from the piezoelectric sensor exceeds a threshold value.

  In the sleep stage detection method, acquiring the body motion signal with high accuracy is extremely important for accurately calculating the sleep stage.

  When the present inventors created a body motion sensor using a piezoelectric element, it was found that the body motion signal is affected by the temperature of the body motion sensor (that is, the piezoelectric element). A specific example is shown in FIG.

  In FIG. 19, it is assumed that the subject on the bed rolls over at the timing of Y1 and changes from a state in which there is no body on the piezoelectric element to a state in which it exists. In that case, the piezoelectric element generates a voltage change due to body movement in the period Y2. If this voltage change exceeds a preset upper threshold (or lower threshold), it can be determined that one body movement has occurred.

  However, at the same time, the temperature of the piezoelectric element rises due to heat conduction due to the body getting on the piezoelectric element. When the temperature of the piezoelectric element changes, polarization occurs in the piezoelectric element due to thermal expansion or contraction, and a generated signal (body motion signal) changes. The change in temperature of the piezoelectric element due to the heat conduction occurs later than the timing of turning over. For this reason, a voltage change due to a temperature change is generated in the period Y3 after a few seconds have elapsed after the change of the generated signal due to turning over in the period Y2.

  If this voltage change exceeds the upper threshold value (or falls below the lower threshold value), it is determined that the second body movement has occurred. In this way, although one body movement actually occurs, it is counted as two body movements, and thus the frequency of body movement is erroneously measured.

  As described above, since the generated signal of the piezoelectric element is affected by the temperature change, there arises a problem that the accuracy of the body motion frequency is lowered and the calculation accuracy of the sleep stage is deteriorated.

  As described above, according to the eighth embodiment to the twelfth embodiment, the degree of the influence of the temperature on the body motion signal is proportional to the time derivative of the temperature. By subtracting the value obtained by multiplying the proportional constant by the time derivative of the detected temperature from the generated signal of the piezoelectric element or adding it to the threshold value, the influence of temperature can be corrected. Therefore, the influence of the temperature change on the body motion signal can be eliminated and the body motion frequency can be obtained with high accuracy.

  As described above, since the eighth embodiment to the twelfth embodiment can prevent the influence of the temperature change on the generated signal of the piezoelectric element, they are very useful for solving the above problem.

-Thirteenth Embodiment Hereinafter, an embodiment relating to the removal of the influence on the signal voltage of the warp caused by the curl generated when winding the reel in the piezoelectric cable will be described.

  FIG. 20 is a schematic plan view of the biological information detection mat according to the present embodiment.

  The biological information detection mat 131 has a structure in which a piezoelectric cable 133 is attached to and fixed by an adhesive tape (hereinafter simply referred to as a tape) 134 over the entire length of the substrate 132 integrally with the substrate 132. ing. A signal generated by the piezoelectric cable 133 is extracted to the outside through a lead wire 135. The lead wire 135 is composed of two wires 135a and 135b, one of which is electrically connected to the anode side of the piezoelectric element 133 and the other lead wire 135b is electrically connected to the cathode side.

  The biometric information detection mat 131 is installed by a user under a mattress or mattress during sleep, and the user detects biometric information during sleep. More specifically, body movement during sleep is transmitted to the substrate 132, which is detected by the piezoelectric cable 133 and converted into an electrical signal, which is transmitted to an electrical signal processing circuit (not shown) via the lead wire 135. The

  The electric signal processing circuit is a circuit having an amplifier, an A / D converter, and signal processing means, and detects a body motion signal, a respiratory signal, a heartbeat signal, etc., and provides a user with necessary information Is configured. The body motion signal, the respiration signal, and the heartbeat signal are superimposed on the signal generated from the piezoelectric cable 133. The body motion signal is a signal having a certain amplitude or more, and the respiration signal has a frequency of 0.2 Hz to 0.4 Hz. As a periodic signal, the heartbeat signal can be recognized as a periodic signal of 0.8 Hz to 1.5 Hz and separated from the generated signal.

  FIG. 21 is a diagram schematically showing a state of the biological information detection mat 131 before the piezoelectric cable 133 is attached with the tape 134 as seen from a direction perpendicular to the length direction of the piezoelectric cable 135. is there. However, FIG. 21A shows a state before pasting in the biological information detection mat 131. FIG. 21B shows a state before sticking in the conventional biological information detection mat 136.

  The piezoelectric cable is always warped during the manufacturing process. Therefore, when the piezoelectric cable 137 is attached to the substrate 138 with the tape 139 in a warped state as in the case of the conventional biological information detection mat 136 shown in FIG. By simple procedure. That is, the tape 139 is affixed in advance to the side 137a where the warp of the piezoelectric cable 137 is convex or the side where the warp is concave. Next, one end side of the piezoelectric cable 137 is affixed to the substrate 138 with the tape 139, and then gradually affixed to the substrate 138 toward the other end side. By doing so, the piezoelectric cable 137 can be attached to a predetermined location on the substrate 138.

  As described above, in order to attach the warped piezoelectric cable 137 so that the direction orthogonal to the warping direction is parallel to the main surface of the substrate 138, first, one end side of the piezoelectric cable 137 is attached to the substrate 138. It is extremely difficult to attach to a predetermined position on the substrate 138 while adjusting the position of the other end of the piezoelectric cable 137.

  Thus, when the piezoelectric cable 137 is attached to the substrate 138 with the tape 139 in a warped state, when the tape 139 is peeled off, the piezoelectric cable 137 is warped in the same direction as before the attachment. Can be confirmed.

  On the other hand, in the living body information detection mat 131 of the present embodiment, as shown in FIG. 21A, the piezoelectric cable 133 is attached to the substrate 132 with a tape 134 without warping. Yes. By doing so, the internal stress in the piezoelectric cable 133 becomes substantially zero, and the generated signal strength can be prevented from being suppressed.

  FIG. 22 shows the difference in signals generated in the piezoelectric cable when the direction of application and the direction of deformation with respect to the substrate are variously changed when the warped piezoelectric cable is attached to the substrate. Line a in FIG. 22 is a case where the warp convex side of the piezoelectric cable is pasted so as to face away from the substrate. Further, row b is a case where the piezoelectric cable is attached so that the convex side of the warp faces the substrate. Further, line c is a case where the piezoelectric cable is attached so that the convex side of the warp is on the back side of the page. Line d is a case where the piezoelectric cable is attached so that the convex side of the warp is on the front side of the page.

  Further, row A in FIG. 22 is a case where the substrate on which the piezoelectric cable is attached is pushed and deformed from the piezoelectric cable side. Further, row B is a case where the substrate on which the piezoelectric cable is attached is pushed and deformed from the side opposite to the piezoelectric cable.

  FIG. 23 is a schematic diagram of an apparatus (CreepMeter RE2-30005B manufactured by Yamaden Co., Ltd.) in which an experiment for deforming the biological information detection mat was performed in order to obtain the experimental data shown in FIG. A constant load was applied to the biological information detection mat at a constant speed using the apparatus shown in FIG.

  The apparatus is an apparatus that detects a load applied to the probe 141 from below by the load cell 142 and raises the stage 143 until the load reaches a predetermined value. A spacer 144 is disposed on the stage 143 so that the inspection object is bent. On the spacer 144, the biological information detection mat 145 is installed as the inspection object.

  The biological information detection mat 145 as the object to be inspected has a size of 30 cm × 10 cm, a substrate 146 made of an ABS plate having a thickness of 2 mm, a piezoelectric cable 147 having a length of 28 cm, and a length of the piezoelectric cable 147. It is formed by sticking with a tape 148 so that the vertical direction is parallel to the length direction of the substrate 146.

  The position where the probe 141 pushes the substrate 146 of the biological information detection mat 145 is the center in the longitudinal direction of the substrate 146 and is a position shifted by 1 cm from the position of the piezoelectric cable 147. The tip of the probe 141 was a 4 mmφ circular one. Here, the ascending speed of the stage 143 was 10 mm / sec, and the load was 20 N.

  According to FIG. 22, when the direction of warping of the piezoelectric cable 147 is in a plane perpendicular to the main surface of the substrate 145 as in the above “a row” and “b row”, the signal generated by the piezoelectric cable 147 is Relatively small and suppressed. On the other hand, when the direction of warping of the piezoelectric cable 147 is in a plane parallel to the main surface of the substrate 145 as in the “c row” and “d row”, the suppression of the signal generated by the piezoelectric cable 147 is suppressed. can not see.

  FIG. 24 is a schematic diagram for explaining the experimental data shown in FIG. However, FIG. 24A shows a state before the warped piezoelectric cable 147 is attached to the substrate 146. FIG. 24B shows a state after the piezoelectric cable 147 is attached to the substrate 146. FIG. 24C shows a state after the piezoelectric cable 147 is attached to the substrate 146, and is an enlarged view of a circular portion in FIG. However, FIG. 24A, FIG. 24B, and FIG. 24C are all schematic cross-sectional views of the biological information detection mat 147 on a plane parallel to the warp-direction plane of the piezoelectric cable 147. In order to avoid complication, the tape 148 for attaching the piezoelectric cable 147 and the lead wire of the piezoelectric cable 147 are omitted.

  As shown in FIG. 24 (a), the warped piezoelectric cable 147 is attached to the main surface of the substrate 146 so that the substrate 146 is attached to the piezoelectric cable 147 as shown in FIG. 24 (b). The piezoelectric cable 147 has a shape that matches the shape of the main surface of the substrate 146 because it is harder. However, as shown in FIG. 24C, restoring forces Fa and Fb are exerted in the attached piezoelectric cable 147 to return to the original shape with warping.

  In the piezoelectric cable 147, the piezoelectric element 150 that covers the core wire 149 in a columnar shape is usually made of a flexible material, and the mesh electrode 151 that wraps the piezoelectric element 150 is also usually made thin and flexible. Fa and Fb are generated when the core wire 149 in the piezoelectric cable 147 and the coating layer 152 covering the whole are restored. In that case, the piezoelectric element 150 in the piezoelectric cable 147 is polarized by receiving stress due to the restoring forces Fa and Fb. Since electric charges are supplied from the electric signal processing circuit to the core wire 149 and the mesh electrode 151 so as to cancel the polarization inside the piezoelectric element 150, the potential difference between the core wire 149 and the mesh electrode 151 becomes 0 in a steady state. Yes.

  In this state, as shown in “a row B column” and “b row A column” in FIG. 22, when the substrate 146 is displaced in the same direction as the warp, the action of being released from the restoring forces Fa, Fb Since the action of generating a signal due to the displacement is in the opposite direction, a net signal is generated, which is a cause of signal intensity suppression.

  On the other hand, as shown in “a row A column” and “b row B column” in FIG. 22, when the substrate 146 is displaced in the direction opposite to the warp, the restoring forces Fa and Fb of the core wire 149 and the covering layer 152 are repulsive forces. Even if the amount of displacement of the substrate 146 is the same as the case of displacement in the same direction as the warp described above, the speed to reach the amount of displacement is suppressed by the repulsive force. Electric charges for canceling the polarization are supplied, causing the peak intensity of the generated signal to be suppressed.

  As described above, when the piezoelectric cable 147 is attached to the substrate 146 in a state where the warping direction is in a plane perpendicular to the main surface of the substrate 146, the displacement direction of the substrate 146 with respect to the warping direction is “same”. Therefore, the generated signal strength is suppressed in either case of “reverse”.

  In biological information detection mat 131 in the present embodiment, piezoelectric cable 133 without warping is affixed to substrate 132 with tape 134. Therefore, the internal stress of the piezoelectric cable 133 is substantially 0, and the signal strength generated in the piezoelectric cable 133 is not suppressed. Therefore, the signal intensity is increased as compared with the case where the tape is attached with warping, and the effects of improving sensitivity and improving the S / N ratio can be achieved.

  FIG. 25 is a diagram showing an effect obtained by removing the warp of the piezoelectric cable 133 like the biological information detection mat 131 in the present embodiment. Line a in FIG. 25 is a case where the warp convex side of the piezoelectric cable is attached to the substrate in the opposite direction to the substrate, similarly to line a in FIG. Further, row e is a case where the warp of the piezoelectric cable is removed and attached to the substrate.

  Furthermore, row A in FIG. 25 is a case where the substrate to which the piezoelectric cable is attached is pushed in from the same side as the piezoelectric cable and deformed, similarly to row A in FIG. Also, row B is a case where the substrate on which the piezoelectric cable is attached is pushed from the side opposite to the piezoelectric cable and deformed, as in row B in FIG. The experimental data shown in FIG. 25 was obtained using the apparatus shown in FIG.

  As is clear from FIG. 25, it can be seen that suppression of the signal intensity from the piezoelectric cable 133 is prevented by removing the warp of the piezoelectric cable 133 as in the biological information detecting mat 131 of the present embodiment.

  FIG. 26 is a diagram for explaining how to obtain the curvature of the piezoelectric cable 133 in the biological information detection mat 131 according to the present embodiment. However, FIG. 26A is an explanatory diagram of obtaining an orthogonal projection line on the main surface of the substrate 132. FIG. 26B is an explanatory diagram for obtaining an orthogonal projection line on a plane perpendicular to the main surface of the substrate 132.

  First, as shown in FIG. 26 (a), the piezoelectric cable 133 is placed on the substrate 132 so as to be attached to the substrate 132 and is as close to no stress as possible so as not to be deformed. In this state, a photograph is taken with a camera from a direction perpendicular to the main surface of the substrate 132. Then, an X axis and a Y axis are set on the main surface of the substrate 132, and each point on the orthogonal projection line 161 (hereinafter also referred to as a first orthogonal projection) 161 from the captured image to the main surface of the substrate 132 is set. Get coordinate data. The spatial resolution in that case may be less than or equal to the extent that the shape of the first orthogonal projection 161 can be reproduced. Next, a least square fitting straight line 162 is obtained from the coordinate data of each point on the orthogonal projection line 161.

  Next, as shown in FIG. 26B, a screen 163 that is parallel to the least-square fitting straight line 162 and parallel to a plane perpendicular to the main surface of the substrate 132 is disposed. Finally, the piezoelectric cable 133 is imaged by a camera from a direction perpendicular to the screen 163, and an orthogonal projection line (hereinafter referred to as a second orthogonal projection) 164 to the screen 163 is obtained from the captured image. Hereinafter, based on the second orthogonal projection 164, the curvature of the piezoelectric cable 133 is obtained.

  FIG. 27 shows the correlation between the curvature of the piezoelectric cable and the peak value of the intensity of the generated signal. The vertical axis represents the maximum amplitude of a signal (see FIG. 25) generated in the piezoelectric cable due to the deformation when the biological information detection mat is deformed by applying a load with a constant load using the apparatus shown in FIG. The horizontal axis represents the maximum curvature in the second orthogonal projection obtained for the piezoelectric cable as shown in FIG. Here, the curvature is the reciprocal of the radius of curvature, and the unit is [/ m].

  As is clear from FIG. 27, the maximum amplitude of the signal decreases as the curvature increases. However, it can be seen that when the curvature is 2 / m or less, the maximum amplitude of the signal is substantially the same as when the curvature is zero. Therefore, in order to obtain the effect of the present embodiment that “the signal strength is increased by pasting the piezoelectric cable 133 without warping to the substrate 132”, in the piezoelectric cable 133 of the present embodiment, FIG. The curvature of the second orthogonal projection 164 obtained as shown in FIG. 6 needs to be 2 / m or less over the entire length. More desirably, it is 1 / m or less over the entire length, and further desirably 0 / m.

  FIG. 28 shows an apparatus for removing the warp of the warped piezoelectric cable in order to obtain the warp-free piezoelectric cable 133 used in the biological information detecting mat 131 of the present embodiment. However, FIG. 28A is a perspective view showing the appearance of the apparatus. FIG. 28 (b) is a plan view of the sample stage.

  In FIG. 28, the piezoelectric cable warp removing device 171 includes a sample stage 172, a fixed mold plate 173 having a curved recess 173a, a movable mold plate 174 having a curved projection 174a fitted to the recess 173a, a movable press plate 175, A camera 176 is provided. The procedure for removing the warp from the warped piezoelectric cable 133a and forming the warp-free piezoelectric cable 133 will be described below with reference to FIGS. 28 (a) and 28 (b).

  First, as shown in FIG. 28 (b), the warped piezoelectric cable 133a includes the bending direction of the concave portion 173a of the fixed mold plate 173 and the convex portion 174a of the movable mold plate 174, and the warping direction of the piezoelectric cable 133a. Are arranged on the sample stage 172 so as to face each other. Next, the movable mold plate 174 is moved toward the fixed mold plate 173, and the piezoelectric cable 133a is sandwiched between the convex portion 174a of the movable mold plate 174 and the concave portion 173a of the fixed mold plate 173, and the piezoelectric cable 133a is opposite to the warp. Mold in the direction.

  At this time, in order to prevent the piezoelectric cable 133a from rotating so that the warping direction of the piezoelectric cable 133a coincides with the bending direction of the concave portion 173a and the convex portion 174a, the movable pressing plate 175 causes the piezoelectric cable 133a to be rotated. The sample table 172 is pressed from the vertical direction. In this case, the pressing force and pressing time of the movable mold plate 174 against the fixed mold plate 173 vary depending on the curvature of the piezoelectric cable 133a in an unloaded state. For this purpose, the shape of the piezoelectric cable 133a in an unloaded state is imaged by the camera 176 installed on the movable holding plate 175 before molding. Then, the maximum curvature of the piezoelectric cable 133a is obtained by image recognition, and the pressing force and time are determined accordingly.

  Thus, by using the piezoelectric cable warp removing device 171, the warp is removed from the warped piezoelectric cable 133 a, and the piezoelectric cable 133 can be formed into a substantially straight warp-free piezoelectric cable 133.

  FIG. 29 is a schematic cross-sectional view of the piezoelectric cable 133 from which the warp has been removed using the piezoelectric cable warp removing device 171 shown in FIG. As can be seen from FIG. 29, the cross section of the core wire 181 is changed from a circular shape before pressing to an elliptical shape by being pressed by the fixed mold plate 173 and the movable mold plate 174, and the pressing direction is the short axis in the cross section of the core wire 181. In the direction of 182, the direction perpendicular to the pressing direction is the direction of the long axis 183 in the cross section of the core wire 181. In addition, 184 is a piezoelectric element that covers the core wire 181 in a cylindrical shape, 185 is a mesh electrode that wraps the piezoelectric element 184, and 186 is a covering layer that covers the whole.

  Hereinafter, a method for confirming the cross-sectional shape of the core wire 181 in the piezoelectric cable 133 will be described. First, the piezoelectric cable 133 from which the warp has been removed is cut using a cutter or the like. Further, the cut surface is polished in order to remove the region where the piezoelectric cable 133 is deformed by the stress at the time of cutting. In polishing, first polishing is performed for about 1 mm using No. 800 polishing paper, and then final finishing is performed using No. 1200 polishing paper and then No. 1800 polishing paper.

  When the warp of the piezoelectric cable 133a is removed using the piezoelectric cable warp removing device 171 in this way, the core wire 181 becomes an elliptical shape. Therefore, when pasting on the substrate 132, it is desirable that the minor axis 182 be pasted so as to be perpendicular to the main surface of the substrate 132. The reason is that when the long axis 183 is attached so as to be perpendicular to the main surface of the substrate 132, the piezoelectric element 184 is compressed in the vicinity thereof and is subjected to internal distortion, and depending on the direction of displacement. This is because it leads to suppression of generated signal intensity.

  The shape of the biological information detection mat 131 in the present embodiment is not limited to the shape shown in FIG. That is, the shape of the substrate 132 may be any of a square, a rectangle, a curved shape, and a polygon. Further, the piezoelectric cable 133 may be disposed in the center of the substrate 132 or may be disposed in an annular shape around the substrate 132. Even if a plurality of piezoelectric cables 133 are arranged, they may be connected to each other in parallel.

  Furthermore, in the biological information detection mat 131 of the present embodiment, the piezoelectric cable 133 is fixed to the substrate 132 with the tape 134. However, for example, a method of fixing the piezoelectric cable 133 between the substrate 132 and the second substrate may be used. Further, a method may be used in which a groove is provided in the substrate 132 and the piezoelectric cable 133 is embedded in the groove. A method is provided in which a through hole is provided in the substrate 132 over the entire length in the longitudinal direction of the substrate 132 and the piezoelectric cable 133 is embedded in the through hole. But it ’s okay.

-14th Embodiment This Embodiment is related with the biometric information detection mat using the piezoelectric cable which can remove a curvature easily by shaping | molding.

  The sectional structure of the piezoelectric cable used in the living body information detection mat of the present embodiment is substantially the same as the sectional structure of the piezoelectric cable 133 shown in FIG. 29 in the thirteenth embodiment. Therefore, the following will be described with reference to FIG.

  The core wire 181 of the piezoelectric cable 133 in the living body information detection mat of the present embodiment is made of a tough pitch copper (JIS C1100R) material, and is made of a single wire or a plurality of wires. However, the cross-sectional shape of the core wire 181 is within a circle having a diameter of 0.7 mm.

  The tough pitch copper not only has a high electrical conductivity of 349 W / m · K, but also has a picker hardness of 55 HV to 120 HV. Therefore, for example, it is possible to easily remove the warp by molding using the piezoelectric cable warp removing device 171 shown in FIG. Furthermore, since the diameter of the core wire 181 is as thin as 0.7 mm or less, it is possible to obtain an effect that the removal of the warp by the molding becomes easier.

  In addition, the material of the said core wire 181 is not limited to the said tough pitch copper, If the Picker hardness is 150 HV or less, the effect of this Embodiment will generate | occur | produce. Here, the picker hardness is preferably as low as possible, more preferably 120 HV or less, and even more preferably 100 HV or less.

Fifteenth Embodiment This embodiment relates to a biological information detection mat using a piezoelectric cable different from that of the fourteenth embodiment, in which warpage can be easily removed by molding.

  The sectional structure of the piezoelectric cable used in the living body information detection mat of the present embodiment is substantially the same as the sectional structure of the piezoelectric cable 133 shown in FIG. 29 in the thirteenth embodiment. Therefore, the following will be described with reference to FIG.

  The covering layer 186 of the piezoelectric cable 133 in the living body information detection mat of the present embodiment is made of soft polyvinyl chloride and has a thickness of 0.5 mm or less. Soft polyvinyl chloride has a small Shore hardness of 12 to 16 and can be easily deformed. Therefore, for example, by using the piezoelectric cable warp removing device 171 shown in FIG. 28, it is possible to easily remove the warp. Further, since the thickness is as thin as 0.5 mm or less, it is possible to obtain an effect that the removal of the warp by the molding becomes easier.

  Note that the material of the covering layer 186 is not limited to the soft polyvinyl chloride, and the effect of the present embodiment is generated if the Shore hardness is 20 or less. Here, the lower the Shore hardness, the more desirable, 16 or less is more desirable, and 12 or less is more desirable.

As described above, the biological information detection mat of the present invention is
A first substrate 2, 12, 22, 32, 42, 52, 62;
A piezoelectric element that is provided integrally with the first substrate 2, 12, 22, 32, 42, 52, 62 and detects vibrations of the first substrate 2, 12, 22, 32, 42, 52, 62. Elements 3, 13, 23, 33, 43, 53, 63;
The first substrate 2, 12, 22, 32, 42, 52, 62 is provided integrally with the piezoelectric element 3, 13, 23, 33, 43, 53, 63 or the first substrate 2, 12, 22, 32, 42, 52, 62, two regions 5, 15, 26, 37, 46, 46a, 57, 66; 6, 16, 27, 38, 47, which have different elastic coefficients. Spacers 4, 14, 24, 34, 44, 44a, 54, 64 for forming 58, 67 adjacent to each other;
The spacers 4, 14, 24, 34, 44, 44a, 54, 64 constitute one of the two regions 6, 16, 27, 38, 47, 58, 67 having different elastic coefficients.
The piezoelectric elements 3, 13, 23, 33, 43, 53, 63 have two regions 5, 15, 26, 37, 46, 46a, 57, 66; 6, 16, 27, 38 having different elastic coefficients. , 47, 58, 67 or the other of the two regions different from the one of 6, 16, 27, 38, 47, 58, 67, 5, 15, 26, 37, 46, 46a, 57, It is characterized by being arranged from the vicinity of the boundary between the two regions in 66 to the opposite side of the boundary.

  According to the above configuration, the two regions 5, 15, 26, 37, 46, 46a, 57, 66; 6, 16, 27, 38, 47, 58, 67 having different elastic coefficients from each other, or The piezoelectric elements 3, 13, 23, from the vicinity of the boundary between the two regions in the other 5, 15, 26, 37, 46, 46a, 57, 66 to the opposite side of the boundary between the two regions. 33,43,53,63 are arranged.

  Therefore, when the body motion is transmitted to the living body information detection mat, the second position is located above the other 5, 15, 26, 37, 46, 46a, 57, 66 of the two regions having different elastic coefficients. One substrate 2, 12, 22, 32, 42, 52, 62 is displaced in the thickness direction and vibrates. In that case, the piezoelectric elements 3, 13, 23, 33, 43, 53, 63 located on the other 5, 15, 26, 37, 46, 46a, 57, 66 of the two regions are mainly pulled. A force acts, and a voltage signal is generated between the electrodes of the piezoelectric elements 3, 13, 23, 33, 43, 53 and 63. Further, the piezoelectric elements 3, 13, 23, 33, 43, 53 are present due to the presence of the other 5, 15, 26, 37, 46, 46a, 57, 66 having the larger elastic coefficient of the two regions. , 63 increases, the S / N ratio of the voltage signal is improved.

  On the other hand, the spacers 4, 14, 24, 34, 44, 44a, 54, and 64 are located on the one of the two regions formed by the spacers 4, 14, 27, 38, 47, 58, and 67. The piezoelectric elements 3, 13, 23, 33, 43, 53, 63 are relatively difficult to vibrate. For this purpose, the piezoelectric element is located at the boundary between the one of the two regions 6,16,27,38,47,58,67 and the other 5,15,26,37,46,46a, 57,66. 3,13,23,33,43,53,63 is bent and a bending force is applied, and a larger signal is generated between both electrodes of the piezoelectric element 3,13,23,33,43,53,63. Strength is generated. Therefore, it is possible to further improve the S / N ratio.

  That is, according to the present invention, it is possible to improve sensitivity when detecting body motion vibration.

但し
Ｗ：上記第１の基板における上記境界に平行な方向への幅(mm)
ｈ：上記第１の基板の厚さ(mm)
Ｌ：上記境界から上記境界に対向する端部までの距離(mm)
Ｅ_f：上記第１の基板の曲げ弾性率(ＭＰa) Moreover, in the biological information detection mat of one embodiment,
The vicinity of the boundary between the two regions means the distance x (mm) from the boundary between the two regions in the other 5, 15, 26, 37, 46, 46a, 57, 66 of the two regions. Is a region represented by the following formula.

W: width in the direction parallel to the boundary in the first substrate (mm)
h: thickness of the first substrate (mm)
L: Distance from the boundary to the end facing the boundary (mm)
E _f : bending elastic modulus (MPa) of the first substrate

The right side in the above formula shows the curvature of the first substrate 2, 12, 22, 32, 42, 52, 62 when the first substrate 2, 12, 22, 32, 42, 52, 62 is bent. Represents the distance x ₀ from the boundary to the position where becomes the largest.

According to this embodiment, the distance x from the boundary between the two regions to the vicinity of the boundary between the two regions is the other 5, 15, 26, 37, 46, 46a, 57 of the other region. in 66, it is set to be less than the distance x _0. The piezoelectric elements 3, 13, 23, 33, 43, 53, and 63 are disposed over both the region satisfying x ≦ x ₀ and the other regions.

Therefore, if the user's body movement is transmitted to the first substrate 2,12,22,32,42,52,62, the piezoelectric near distance x x = x ₀ from the boundary of the two regions The element 3, 13, 23, 33, 43, 53, 63 has a large fold. Therefore, a large signal intensity can be obtained by the piezoelectric effect due to the vertical stress caused by the bending force, and the S / N ratio can be improved to improve the sensitivity.

Moreover, in the biological information detection mat of one embodiment,
The piezoelectric elements 3, 13, 23, 33, 43, 53, 63 are piezoelectric cables.

  According to this embodiment, the piezoelectric elements 3, 13, 23, 33, 43, 53, 63 are constituted by piezoelectric cables. Therefore, the piezoelectric effect due to “elongation” and “folding” appears more prominently than when a piezoelectric film is used. As a result, when the first substrate 2, 12, 22, 32, 42, 52, 62 vibrates in the thickness direction, the piezoelectric effect due to the shear stress due to the tensile force and the piezoelectric effect due to the vertical stress due to the bending force. The effect can be detected with high accuracy, and the vibration in the thickness direction can be effectively detected.

Moreover, in the biological information detection mat of one embodiment,
A second substrate 25, 35, 45, 55, 65 disposed below the first substrate 22, 32, 42, 52, 62 and the piezoelectric elements 23, 33, 43, 53, 63;
Between the first substrate 22, 32, 42, 52, 62 and the second substrate 25, 35, 45, 55, 65, the two regions 26, 37, 46, 46a having different elastic coefficients from each other. , 57, 66; 27, 38, 47, 58, 67 are formed.

  According to this embodiment, two elastic coefficients different from each other are provided between the first substrate 22, 32, 42, 52, 62 and the second substrate 25, 35, 45, 55, 65. Regions 26, 37, 46, 46a, 57, 66; 27, 38, 47, 58, 67 are formed. Therefore, it is integrally installed on the lower surface of the first substrate 22, 32, 42, 52, 62, and constitutes one of the two regions 27, 38, 47, 58, 67. The spacers 24, 34, 44, 44a, 54, and 64 are not exposed to the outside. Therefore, the risk of injury to the user can be eliminated by the protrusions such as the spacers 24, 34, 44, 44a, 54, 64 and the like.

Moreover, in the biological information detection mat of one embodiment,
The first substrate 32 is divided into a plurality of partial substrates 32a, 32b, 32c along the boundary between the two regions 37, 38.
The division position of the first substrate 32 is on the boundary between the two regions 37 and 38 or on the position on the other side of the two regions 37 and 38 with respect to the boundary between the two regions 37 and 38. It is.

  According to this embodiment, the first substrate 32 is divided on the boundary between the two regions 37 and 38 having different elastic coefficients from each other or on the other 37 side from the boundary. And divided along the boundary. Therefore, when the user's body movement is transmitted to the first substrate 32, the piezoelectric element 33 is bent at the division position on the first substrate 32. In that case, the bending rigidity of the entire biometric information detection mat is reduced by the bending rigidity of the first substrate 32. For this reason, the piezoelectric element 33 is greatly bent, and the piezoelectric effect due to the vertical stress caused by the bending force is further exerted, so that a larger signal intensity can be obtained. That is, the S / N ratio can be further improved.

Moreover, in the biological information detection mat of one embodiment,
There are a plurality of two regions 46, 46a; 47 having different elastic coefficients.

  According to this embodiment, a plurality of the two regions 46, 46a; 47 having different elastic coefficients from each other are provided. Therefore, a plurality of places where the piezoelectric element 43 is bent can be provided, and a signal of the piezoelectric effect due to the vertical stress can be obtained in more detail. Therefore, it is possible to further improve the sensitivity by further improving the S / N ratio.

Moreover, in the biological information detection mat of one embodiment,
Of the two regions 57 and 58 having different elastic coefficients, the other 57 is constituted by an elastic body 56.

  When the other 57 of the two regions 57 and 58 having different elastic coefficients is constituted by a space, the first weight is increased because the user's weight is large or the user's body has a protrusion. The substrate 52 is greatly pushed down and may come into contact with the mattress or the second substrate 55. In that case, vibration due to body movement in the first substrate 52 is hindered.

  According to this embodiment, the other 57 of the two regions 57 and 58 is constituted by the elastic body 56. Accordingly, the first substrate 52 can be prevented from being pushed down by the elastic force of the elastic body 56, and the first substrate 52 can be prevented from coming into contact with the mattress or the second substrate 55.

Moreover, the body motion sensor of other embodiment is
Piezoelectric elements 73, 103, 113, 123 that detect the movement of the human body and output body movement signals;
Temperature measuring sections 75, 105, 115, and 125 that are thermally connected to the piezoelectric elements 73, 103, 113, and 123, measure the temperatures of the piezoelectric elements 73, 103, 113, and 123, and output temperature signals. When,
Body motion determination units 83 and 91 that determine whether or not the strength of the body motion signal from the piezoelectric elements 73, 103, 113, and 123 exceeds a preset threshold value,
Based on the temperature signals from the temperature measuring sections 75, 105, 115, and 125, a time differential value of the measured temperature is calculated, and a value obtained by multiplying the calculated time differential value of the measured temperature by a constant is used as the piezoelectric element. Temperature correction units 79 to 82, 91 for correcting the influence of temperature on the body motion signal by adding or subtracting to the body motion signal from 73, 103, 113, 123 or the threshold value in the body motion determination unit 91; It is characterized by having.

  According to the above configuration, body motion signals from the piezoelectric elements 73, 103, 113, 123 are obtained by the temperature correction units 79 to 82, 91 based on temperature signals from the temperature measuring units 75, 105, 115, 125. A correction value for correcting the influence of temperature on the body motion is obtained and added to or subtracted from the body motion signal or the threshold value of the body motion determination unit 91. Therefore, the influence of temperature on the body motion signal can be canceled, and the presence or absence of body motion can be accurately determined based only on the value motion signal caused by the body motion.

In the body motion sensor of one embodiment,
The piezoelectric elements 103 and 113 are piezoelectric films or piezoelectric cables.

  There is a large difference in the range of body movement during sleep among individuals. According to this embodiment, by using the piezoelectric film 103 as the piezoelectric element, it is possible to easily cope with individual differences in the body movement range.

  On the other hand, in the piezoelectric cable, the piezoelectric effect due to “elongation” and “bending” appears remarkably as compared with the piezoelectric film. Therefore, by using the piezoelectric cable 113 as the piezoelectric element, it is possible to accurately detect the movement of the human body during sleep.

In the body motion sensor of one embodiment,
The temperature measuring sections 75, 105, 115, and 125 are any one of a thermocouple, a thermistor, and a thermopile.

  The temperature measuring sections 75, 105, 115, and 125 are preferably small because they can measure a relatively narrow range with high accuracy and are placed in the futon. According to this embodiment, the temperature measuring sections 75, 105, 115, and 125 are constituted by any one of a thermocouple, a thermistor, and a thermopile. Therefore, desirable requirements in the temperature measuring sections 75, 105, 115, and 125 are satisfied, and the temperatures of the piezoelectric elements 73, 103, 113, and 123 can be detected with high accuracy.

In the body motion sensor of one embodiment,
A heating unit 127 for heating the piezoelectric element 123 and the temperature measuring unit 125;
Based on the temperature signal from the temperature measuring unit 125 heated by the heating unit 127 and the body motion signal from the piezoelectric element 123, the temperature correction units 79 to 81 and the time differential value of the measured temperature and the above The above constant is obtained by performing linear approximation with the voltage value of the body motion signal to obtain the slope of the approximate line.

  According to this embodiment, the heating unit 127 for heating the piezoelectric element 123 and the temperature measuring unit 125 is provided. Therefore, when the temperature correction units 79 to 81 approximate the time differential value of the measured temperature and the voltage value of the body motion signal, the piezoelectric element 123 and the temperature measuring unit 125 are heated from the outside. It is not necessary to prepare the heating means, and the correlation equation between the time differential value of the measured temperature and the voltage value of the body motion signal from the piezoelectric element 123 can be calculated under the use environment of the user.

  That is, according to this embodiment, it is possible to eliminate the influence of manufacturing variations and use environments for each body motion sensor, and perform correction to cancel the influence of temperature with higher accuracy.

Moreover, the sleep sensing system of other embodiment is
With the body motion sensor
further,
A sleep stage calculation unit 84 that calculates a sleep stage based on the number of presence or absence of body movement determined by the body movement determination units 83 and 91 in the body movement sensor;
Based on the body motion signal from the body motion sensor,
Based on the body motion signal from the body motion sensor, a respiration detection unit that detects respiration,
At least one of a snoring detection unit for detecting snoring based on the body motion signal from the body motion sensor is provided.

  According to the above configuration, in the sleep sensing system including the body motion sensor, the presence or absence of body motion determined by the body motion determination units 83 and 91 of the body motion sensor, and the body from the body motion sensor. Based on the motion signal, at least one of sleep stage calculation, heartbeat detection, respiration detection, and snoring detection is performed. Therefore, based on the presence / absence of body motion correctly determined by the body motion signal with the temperature effect corrected, and the body motion signal with the temperature effect corrected, the sleep stage, the heart rate, the breathing and It becomes possible to accurately detect a signal resulting from the snoring.

1,11,21,31,41,51,61,71,101,111,121,131,145 ... Biological information detection mat 2,12,72,102,112,122,132,146 ... Substrate 3,13 , 23,33,43,53,63,113,133,147 ... piezoelectric cable 4,14,24,34,44,44a, 54,64,144 ... spacer 5,15,26,37,46,46a, 57, 66... Region where voids are present 6, 16, 27, 38, 47, 58, 67 .. region where voids are not present 22, 32, 42, 52, 62... First substrate 32a, 32b, 32c. , 35, 45, 55, 65 ... second substrate 36 ... dividing groove 56 ... elastic body 73, 123, 150, 184 ... piezoelectric element 74, 124 ... piezoelectric element lead wire 75, 105, 105a, 105b, 105c, 115, 115a, 115b, 115c, 125 ... Temperature measuring unit 76,106,116,126 ... Temperature measuring unit lead wire 77, 107, 117, 129 ... buffer material 78 ... voltage measurement unit 79 ... temperature measurement unit 80 ... time differential calculation unit 81 ... correction value calculation unit 82 ... addition unit 83, 91 ... body motion frequency calculation unit 84 ... sleep stage calculation Part 85 ... Display part 103 ... Piezoelectric film 104 ... Piezoelectric film lead wires 114 and 135 ... Piezoelectric cable lead wire 127 ... Heating part 128 ... Heating part lead wires 134 and 148 ... Tape 141 ... Probe 142 ... Load cell 143 ... Stages 149 and 181 ... core wires 151, 185 ... mesh electrodes 152, 186 ... coating layer 161 ... first orthographic projection 162 ... least square fitting straight line 163 ... screen 164 ... second orthographic projection 171 ... piezoelectric cable warp removing device 172 ... sample stand 173 ... Fixed mold plate 174 ... Movable mold plate 175 ... Movable holding plate 176 ... Cameras Fa, Fb ... Restoring force

Claims (5)

A first substrate;
A piezoelectric element that is provided integrally with the first substrate and detects vibration of the first substrate;
A spacer that is integrally provided on the first substrate, and that is provided on the lower side of the piezoelectric element or the first substrate to form two regions having mutually different elastic coefficients adjacent to each other;
The spacer constitutes one of the two regions having different elastic coefficients from each other,
The piezoelectric element is arranged over the two regions having different elastic coefficients from each other, or from the vicinity of the boundary between the two regions in the other of the two regions different from the one to the opposite side of the boundary. A biological information detection mat characterized by being made. The biological information detection mat according to claim 1,
The vicinity of the boundary between the two regions is a region in which the distance x (mm) from the boundary between the two regions is represented by the following formula in the other of the two regions. Biometric information detection mat.

W: width in the direction parallel to the boundary in the first substrate (mm)
h: thickness of the first substrate (mm)
L: Distance from the boundary to the edge facing the boundary (mm)
E _f : bending elastic modulus (MPa) of the first substrate In the living body information detection mat according to claim 1 or 2,
A second substrate disposed below the first substrate and the piezoelectric element;
The biological information detection mat, wherein two regions having different elastic coefficients are formed between the first substrate and the second substrate. In the biological information detection mat according to any one of claims 1 to 3,
The first substrate is divided into a plurality of partial substrates along a boundary between the two regions,
The biological information detection mat, wherein the division position of the first substrate is on the boundary between the two regions or on the other side of the two regions with respect to the boundary between the two regions. . In the living body information detection mat according to any one of claims 1 to 4,
The biological information detection mat, wherein the other of the two regions having different elastic coefficients is made of an elastic body.

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